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RE: Defraging the excahgne DB
by Borders, Rich 08 Jun '04

08 Jun '04

> -----Original Message----- > From: Mark Simmons [mailto:mds@gbnet.net] > Sent: Tuesday, June 08, 2004 7:45 AM > To: SKIP HOFMANN > Cc: 'avarni(a)tech.cj.com'; Waters, G Scott THE LOG.SEC TEAM; > Borders, Rich; toasters(a)mathworks.com > Subject: Re: Defraging the excahgne DB > > Turning the question around, why would it not be safe to > defragment a file on the filer? Filer defrag requires two things ( as a general rule ): 20 percent volume space free, and no snapshots. The rest is shuffling blocks into a more application friendly pattern. > From the point of view of the client nothing should change surely? If you do offline defrags and meet the above requirements, you will effectively have an offline application and a well organized 'efficient' database afterwards. > If it did, that would be a fairly significant problem with > all files, not just Exchange's database. Technically, you can defrag a file, or the volume. The wafl scan reallocate function is trying to get the blocks closer to their layer 0 and one pointers. Defrags are really only a problem if you don't get the first two pre-req's right. > > SKIP HOFMANN wrote: > > >If you use Waffle scan then this defrags the entire vol > right? See above. > And if so is > >it safe to use on your exchange DB? Yes. > >At least on 6.3.2 -- I've noticed that WAFL SCAN REALLOCATE will > >'pause' indefinately IFF you're over your snapshot reserve. It is usually a funciton of not finding any blocks that aren't in worst fragmented shape that what you are already in. A factor of 20% free volume space with NO snapshots all but ensures this will not happen. > Otherwise > >I've run this many times with no problems. Make sure you aren't > >over your snapshot reserve and your scan should 'continue'. You should have no snapshots. > > > >On Mon, 7 Jun 2004, Waters, G Scott THE LOG.SEC TEAM wrote: > > > >] > >] WOW ... this is the exact opposite of what NetApp support told me. > >] > >] On a volume used for storing Exchange data, the WAFL SCAN > REALLOCATE > >command > >] will never complete. No one in NGS support should have told you it will never complete. In 6.3 and greater, it was more optimized and cleaned up, but that was a testamanet to the way block handling was done and some major efficiencies that were built into the OS of Data OnTap. > It goes for a while and then stalls. See above. > >] We monitor the layout ratios weekly and schedule down time > to perform an > >] offline DEFRAG every 4 - 6 weeks. The remarkable thing about an offline defrag is that it effectively copies the entire mailstore in application defrag back to the Filer. This means that the application is defraged as it is written. The wafl is defragged due to the nature of the blockmap and nvram/journaling. It is almost perfect. > >] This is all based on information received at the time ... > If NetApp has > >] fixed this then someone enlighten me. It is fixed, and getting better. Keep your eye open as there will be some new things to come also. I would also like to offer a thinking 'outside the box' and say that it is a cool idea to QSM the mail store from one volume to another since a QSM is a process that is going to defrag on WAFL ( not application though ) and then update on a scheduled basis. Once snapmirrored, you can stop and quiesce the application, then quiesce and break the QSM and that makes the destination read / writable. You point the exchange server to the destination, and voila, you have a reallocate and only a short downtime. > >] > >] - Scott W. That is all for now. /rich

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RE: Defraging the excahgne DB
by SKIP HOFMANN 08 Jun '04

08 Jun '04

If you use Waffle scan then this defrags the entire vol right? And if so is it safe to use on your exchange DB? If it is then that would be greate -----Original Message----- From: avarni(a)tech.cj.com [mailto:avarni@tech.cj.com] Sent: Monday, June 07, 2004 10:19 AM To: Waters, G Scott THE LOG.SEC TEAM Cc: SKIP HOFMANN; 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB At least on 6.3.2 -- I've noticed that WAFL SCAN REALLOCATE will 'pause' indefinately IFF you're over your snapshot reserve. Otherwise I've run this many times with no problems. Make sure you aren't over your snapshot reserve and your scan should 'continue'. On Mon, 7 Jun 2004, Waters, G Scott THE LOG.SEC TEAM wrote: ] ] WOW ... this is the exact opposite of what NetApp support told me. ] ] On a volume used for storing Exchange data, the WAFL SCAN REALLOCATE command ] will never complete. It goes for a while and then stalls. ] ] We monitor the layout ratios weekly and schedule down time to perform an ] offline DEFRAG every 4 - 6 weeks. ] ] This is all based on information received at the time ... If NetApp has ] fixed this then someone enlighten me. ] ] ] - Scott W. ] ] ] -----Original Message----- ] From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] ] Sent: Thursday, June 03, 2004 2:31 PM ] To: 'Borders, Rich'; toasters(a)mathworks.com ] Subject: RE: Defraging the excahgne DB ] ] ] Hi ] ] I just got done talking with support at Netapp, and they told me that doing ] an offline defrag of my exchange DB using the esutil will have absolutely no ] impact on the exchange DB on the filer, and they also told me that in order ] to defrag the exchange DB I must use the fillers Waffle utility to do this ] and that this would also defragment everything on the vol. They said that ] it's the responsibility of the file system on the filer to determine if a ] vol is fragmented or not, this includes all data on the vol. So knowing this ] is it safe to defrag a vol that contains an exchange DB?? ] ] Thanks again for your help it is much appreciated ] ] Skip ] ] -----Original Message----- ] From: Borders, Rich [mailto:Rich.Borders@netapp.com] ] Sent: Thursday, June 03, 2004 11:13 AM ] To: SKIP HOFMANN; toasters(a)mathworks.com ] Subject: RE: Defraging the excahgne DB ] ] <<>> ] ] ] From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] ] Sent: Thursday, June 03, 2004 1:33 PM ] To: toasters(a)mathworks.com ] Subject: Defraging the excahgne DB ] ] ] ] Howdy ] ] ] ] I have my exchange 5.5 DB pub and priv and my filler it's a ] FAS250 and I want to know a few things ] ] ] ] #1 can I run the eseutil utility if the DB is on my FAS 250 to ] defrag the DB? ] ] ] ] ] ] <<< This is doable as it is an offline defrag. The curious thing about ] doing this is that you are accomplishing the APPLICATION defrag, and at ] the same time getting a great by-product of a WAFL defrag. ( Essentially ] a database re-write ) >>> ] ] ] ] ] ] ] ] #2 is it the filer that determines if the exchange DB is ] fragmented or not, and if it is how would I defrag the DB? ] ] ] ] <<<The Application can fragment ( very common and accounted for by an ] online and offline defrag funciton in Exchange ) and the Filer can ] fragment. I say that tounge in cheek because the fragmentation is really ] only identified when you access the data. Since the database is one ] large file the request for data in it is atypical, the data 'fragments' ] over time. The blocks of the filer rarely match up to the blocks of the ] database, so the issues becomes when you want to get a LOT of sequential ] data from a large file ( aka mail store verify ) you will be essentially ] asking the filer to scan through it's blocks at a super high rate of ] speed.>>> ] ] ] ] ] ] #3 what happens to all other data that is stored on the same vol ] as the exchange DB once I defrag this vol? ie snap shots ] ] ] <<<The Mail store can be reallocated or the volume can. I would ] recommend the snapshots be removed as you can really get yourself into a ] pickle by 'RE'-writing a database with an application defrag, or a WAFL ] reallocate. If you are short on space, you need to get the snapshots out ] of there. Snapshots are locked images and if the file system is ] 'fragmented' then it is unlikely that you are doing much more than ] spinning your wheels if you are trying to defragment into a fragemnted ] snapshot. >>> ] ] ] ] #4 I ran a waffle scan and I got a reading of 1.8 si this ] fragmented? ] ] ] That is basically a ratio of actual file size ( df essentially ) to ] block allocation. Ex. A one terabyte volume has a 500 gig database. If ] it's layout is 1 then the File is essentially using the exact number of ] blocks that a Filer of 500 gigs needs. If the layout were 1.8 then the ] 500 gig df would still be 500 but the block allocation would actually be ] closer to the 900 gig . This is usually not an issue until the ratio ] takes the block allocation higher then the volume size. A 2.1 layout ] would mean that a 500 gig df would be 1.05 TB. This means you are ] rescanning on a request of data on the last .05 TB. If the Filer were a ] 900 gig df, then a layout of 1.8 would be MUCH more impactful. It is not ] the end of the world, you just have to manage it. You are on the right ] track I can see, so good luck. ] ] ] ] Thanks a bunch ] ] ] ] Skip ] ] Rich Borders ]

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I'm a new piano tuner to the area
by Doug Freeze 08 Jun '04

08 Jun '04

Hi, I hope you don't mind me writing you. I came across your e-mail address after looking around some websites local to my city and thought I'd ask if you're in need of a professional piano tuner or might know of someone you could forward this e-mail to. I moved into the area a few months ago and I'm tuning for donations until I build-up a customer base so payment is whatever you'd like it to be. I'll travel to the Los Angeles, San Bernardino, Riverside, Ventura and the Orange County areas. Here's a map of where I live in case you'd like to know: http://home.wirelis.com (If this message went out of the area, I apologize. It's not meant to be spam and you'll never receive another message from me again.) You can visit my website or call me if you have any questions. Thanks and I'm sorry if I bothered you or if you don't need this service, Doug Freeze A new resident of Glendora CA. (626) 290-0908 http://dougfreeze.com/piano/index.html http://wirelis.com P.S. You'll never receive another message from me so there's no need to write me back and ask to be removed from my mailing list nor will your e-mail address ever be given away or sold to anyone. See http://dougfreeze.com/wirelis/spam.html to view my position on SPAM and learn how you can help stop it. http://spam.abuse.net

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Tape positioning connected to the F720 filer.
by Harbhajan Julka 07 Jun '04

07 Jun '04

Hello everyone, I have been programming a client using the NetApp F720 server. The GetStateReply from the server returns the position of the media (usually tape) connected to the server. Two of the position structure members: Filemark and Blockno are something that i need to know about. The filemark and blockno respectively indicate the Partition and the BlockLow of the Position on the tape. I need to know if this is right or not. Also, how can i know what is the value of BlockHigh and offset from the server in the GetStateReply? I have tried a backup and then a restore from the tape. A complete restore is successful but fails to restore few files selected from the media. Please help. Any pointers and suggestions appreciated. Cheers, Sonia. --------------------------------- Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger

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RE: Defraging the excahgne DB
by SKIP HOFMANN 07 Jun '04

07 Jun '04

In that case how do you defrag your exchange DB copy the DB to another server with double or triple the amount of the exchange DB size and then run esentuil? Skip _____ From: Waters, George S Mr. [mailto:george.scott.waters@us.army.mil] Sent: Monday, June 07, 2004 10:28 AM To: avarni(a)tech.cj.com Cc: SKIP HOFMANN; 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB I've had it "pause" indefinitely even when I am not over my SnapShot Reserve. NetApp support told me it was a "known issue". I have never been able to get a "WAFL SCAN REALLOCATE" to work on my Exchange Volumes. - Scott W. _____ From: avarni(a)tech.cj.com Sent: Mon 6/7/2004 1:18 PM To: Waters, G Scott THE LOG.SEC TEAM Cc: 'SKIP HOFMANN'; 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB At least on 6.3.2 -- I've noticed that WAFL SCAN REALLOCATE will 'pause' indefinately IFF you're over your snapshot reserve. Otherwise I've run this many times with no problems. Make sure you aren't over your snapshot reserve and your scan should 'continue'. On Mon, 7 Jun 2004, Waters, G Scott THE LOG.SEC TEAM wrote: ] ] WOW ... this is the exact opposite of what NetApp support told me. ] ] On a volume used for storing Exchange data, the WAFL SCAN REALLOCATE command ] will never complete. It goes for a while and then stalls. ] ] We monitor the layout ratios weekly and schedule down time to perform an ] offline DEFRAG every 4 - 6 weeks. ] ] This is all based on information received at the time ... If NetApp has ] fixed this then someone enlighten me. ] ] ] - Scott W. ] ] ] -----Original Message----- ] From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] ] Sent: Thursday, June 03, 2004 2:31 PM ] To: 'Borders, Rich'; toasters(a)mathworks.com ] Subject: RE: Defraging the excahgne DB ] ] ] Hi ] ] I just got done talking with support at Netapp, and they told me that doing ] an offline defrag of my exchange DB using the esutil will have absolutely no ] impact on the exchange DB on the filer, and they also told me that in order ] to defrag the exchange DB I must use the fillers Waffle utility to do this ] and that this would also defragment everything on the vol. They said that ] it's the responsibility of the file system on the filer to determine if a ] vol is fragmented or not, this includes all data on the vol. So knowing this ] is it safe to defrag a vol that contains an exchange DB?? ] ] Thanks again for your help it is much appreciated ] ] Skip ] ] -----Original Message----- ] From: Borders, Rich [mailto:Rich.Borders@netapp.com] ] Sent: Thursday, June 03, 2004 11:13 AM ] To: SKIP HOFMANN; toasters(a)mathworks.com ] Subject: RE: Defraging the excahgne DB ] ] <<>> ] ] ] From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] ] Sent: Thursday, June 03, 2004 1:33 PM ] To: toasters(a)mathworks.com ] Subject: Defraging the excahgne DB ] ] ] ] Howdy ] ] ] ] I have my exchange 5.5 DB pub and priv and my filler it's a ] FAS250 and I want to know a few things ] ] ] ] #1 can I run the eseutil utility if the DB is on my FAS 250 to ] defrag the DB? ] ] ] ] ] ] <<< This is doable as it is an offline defrag. The curious thing about ] doing this is that you are accomplishing the APPLICATION defrag, and at ] the same time getting a great by-product of a WAFL defrag. ( Essentially ] a database re-write ) >>> ] ] ] ] ] ] ] ] #2 is it the filer that determines if the exchange DB is ] fragmented or not, and if it is how would I defrag the DB? ] ] ] ] <<<The Application can fragment ( very common and accounted for by an ] online and offline defrag funciton in Exchange ) and the Filer can ] fragment. I say that tounge in cheek because the fragmentation is really ] only identified when you access the data. Since the database is one ] large file the request for data in it is atypical, the data 'fragments' ] over time. The blocks of the filer rarely match up to the blocks of the ] database, so the issues becomes when you want to get a LOT of sequential ] data from a large file ( aka mail store verify ) you will be essentially ] asking the filer to scan through it's blocks at a super high rate of ] speed.>>> ] ] ] ] ] ] #3 what happens to all other data that is stored on the same vol ] as the exchange DB once I defrag this vol? ie snap shots ] ] ] <<<The Mail store can be reallocated or the volume can. I would ] recommend the snapshots be removed as you can really get yourself into a ] pickle by 'RE'-writing a database with an application defrag, or a WAFL ] reallocate. If you are short on space, you need to get the snapshots out ] of there. Snapshots are locked images and if the file system is ] 'fragmented' then it is unlikely that you are doing much more than ] spinning your wheels if you are trying to defragment into a fragemnted ] snapshot. >>> ] ] ] ] #4 I ran a waffle scan and I got a reading of 1.8 si this ] fragmented? ] ] ] That is basically a ratio of actual file size ( df essentially ) to ] block allocation. Ex. A one terabyte volume has a 500 gig database. If ] it's layout is 1 then the File is essentially using the exact number of ] blocks that a Filer of 500 gigs needs. If the layout were 1.8 then the ] 500 gig df would still be 500 but the block allocation would actually be ] closer to the 900 gig . This is usually not an issue until the ratio ] takes the block allocation higher then the volume size. A 2.1 layout ] would mean that a 500 gig df would be 1.05 TB. This means you are ] rescanning on a request of data on the last .05 TB. If the Filer were a ] 900 gig df, then a layout of 1.8 would be MUCH more impactful. It is not ] the end of the world, you just have to manage it. You are on the right ] track I can see, so good luck. ] ] ] ] Thanks a bunch ] ] ] ] Skip ] ] Rich Borders ]

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RE: Defraging the excahgne DB
by Waters, G Scott THE LOG.SEC TEAM 07 Jun '04

07 Jun '04

WOW ... this is the exact opposite of what NetApp support told me. On a volume used for storing Exchange data, the WAFL SCAN REALLOCATE command will never complete. It goes for a while and then stalls. We monitor the layout ratios weekly and schedule down time to perform an offline DEFRAG every 4 - 6 weeks. This is all based on information received at the time ... If NetApp has fixed this then someone enlighten me. - Scott W. -----Original Message----- From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] Sent: Thursday, June 03, 2004 2:31 PM To: 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB Hi I just got done talking with support at Netapp, and they told me that doing an offline defrag of my exchange DB using the esutil will have absolutely no impact on the exchange DB on the filer, and they also told me that in order to defrag the exchange DB I must use the fillers Waffle utility to do this and that this would also defragment everything on the vol. They said that it's the responsibility of the file system on the filer to determine if a vol is fragmented or not, this includes all data on the vol. So knowing this is it safe to defrag a vol that contains an exchange DB?? Thanks again for your help it is much appreciated Skip -----Original Message----- From: Borders, Rich [mailto:Rich.Borders@netapp.com] Sent: Thursday, June 03, 2004 11:13 AM To: SKIP HOFMANN; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB <<>> From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com] Sent: Thursday, June 03, 2004 1:33 PM To: toasters(a)mathworks.com Subject: Defraging the excahgne DB Howdy I have my exchange 5.5 DB pub and priv and my filler it's a FAS250 and I want to know a few things #1 can I run the eseutil utility if the DB is on my FAS 250 to defrag the DB? <<< This is doable as it is an offline defrag. The curious thing about doing this is that you are accomplishing the APPLICATION defrag, and at the same time getting a great by-product of a WAFL defrag. ( Essentially a database re-write ) >>> #2 is it the filer that determines if the exchange DB is fragmented or not, and if it is how would I defrag the DB? <<<The Application can fragment ( very common and accounted for by an online and offline defrag funciton in Exchange ) and the Filer can fragment. I say that tounge in cheek because the fragmentation is really only identified when you access the data. Since the database is one large file the request for data in it is atypical, the data 'fragments' over time. The blocks of the filer rarely match up to the blocks of the database, so the issues becomes when you want to get a LOT of sequential data from a large file ( aka mail store verify ) you will be essentially asking the filer to scan through it's blocks at a super high rate of speed.>>> #3 what happens to all other data that is stored on the same vol as the exchange DB once I defrag this vol? ie snap shots <<<The Mail store can be reallocated or the volume can. I would recommend the snapshots be removed as you can really get yourself into a pickle by 'RE'-writing a database with an application defrag, or a WAFL reallocate. If you are short on space, you need to get the snapshots out of there. Snapshots are locked images and if the file system is 'fragmented' then it is unlikely that you are doing much more than spinning your wheels if you are trying to defragment into a fragemnted snapshot. >>> #4 I ran a waffle scan and I got a reading of 1.8 si this fragmented? That is basically a ratio of actual file size ( df essentially ) to block allocation. Ex. A one terabyte volume has a 500 gig database. If it's layout is 1 then the File is essentially using the exact number of blocks that a Filer of 500 gigs needs. If the layout were 1.8 then the 500 gig df would still be 500 but the block allocation would actually be closer to the 900 gig . This is usually not an issue until the ratio takes the block allocation higher then the volume size. A 2.1 layout would mean that a 500 gig df would be 1.05 TB. This means you are rescanning on a request of data on the last .05 TB. If the Filer were a 900 gig df, then a layout of 1.8 would be MUCH more impactful. It is not the end of the world, you just have to manage it. You are on the right track I can see, so good luck. Thanks a bunch Skip Rich Borders

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RE: Defraging the excahgne DB
by SKIP HOFMANN 07 Jun '04

07 Jun '04

It seems that Netapp is very confused about this issue and or topic, as I have called into tech support on three separate occasions about this issue and I'm always left feeling more confused than when I called in. Netapp needs to figure this out and give an answer to this question, which I think should be a YES or NO answer. Can the waffle scan safely defrag an exchange DB, if so what are the steps? If a waffle scan cannot defrag an exchange DB then can running eseutil and pointing eseutil to the exchange DB on the filler run, and will it defrag the DB? Thanks Skip _____ From: Waters, G Scott THE LOG.SEC TEAM [mailto:george.scott.waters@us.army.mil] Sent: Monday, June 07, 2004 7:33 AM To: SKIP HOFMANN; 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB Importance: High WOW ... this is the exact opposite of what NetApp support told me. On a volume used for storing Exchange data, the WAFL SCAN REALLOCATE command will never complete. It goes for a while and then stalls. We monitor the layout ratios weekly and schedule down time to perform an offline DEFRAG every 4 - 6 weeks. This is all based on information received at the time ... If NetApp has fixed this then someone enlighten me. - Scott W. -----Original Message----- From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com <mailto:SKIP.HOFMANN@ttisg.com> ] Sent: Thursday, June 03, 2004 2:31 PM To: 'Borders, Rich'; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB Hi I just got done talking with support at Netapp, and they told me that doing an offline defrag of my exchange DB using the esutil will have absolutely no impact on the exchange DB on the filer, and they also told me that in order to defrag the exchange DB I must use the fillers Waffle utility to do this and that this would also defragment everything on the vol. They said that it's the responsibility of the file system on the filer to determine if a vol is fragmented or not, this includes all data on the vol. So knowing this is it safe to defrag a vol that contains an exchange DB?? Thanks again for your help it is much appreciated Skip -----Original Message----- From: Borders, Rich [mailto:Rich.Borders@netapp.com <mailto:Rich.Borders@netapp.com> ] Sent: Thursday, June 03, 2004 11:13 AM To: SKIP HOFMANN; toasters(a)mathworks.com Subject: RE: Defraging the excahgne DB <<>> From: SKIP HOFMANN [mailto:SKIP.HOFMANN@ttisg.com <mailto:SKIP.HOFMANN@ttisg.com> ] Sent: Thursday, June 03, 2004 1:33 PM To: toasters(a)mathworks.com Subject: Defraging the excahgne DB Howdy I have my exchange 5.5 DB pub and priv and my filler it's a FAS250 and I want to know a few things #1 can I run the eseutil utility if the DB is on my FAS 250 to defrag the DB? <<< This is doable as it is an offline defrag. The curious thing about doing this is that you are accomplishing the APPLICATION defrag, and at the same time getting a great by-product of a WAFL defrag. ( Essentially a database re-write ) >>> #2 is it the filer that determines if the exchange DB is fragmented or not, and if it is how would I defrag the DB? <<<The Application can fragment ( very common and accounted for by an online and offline defrag funciton in Exchange ) and the Filer can fragment. I say that tounge in cheek because the fragmentation is really only identified when you access the data. Since the database is one large file the request for data in it is atypical, the data 'fragments' over time. The blocks of the filer rarely match up to the blocks of the database, so the issues becomes when you want to get a LOT of sequential data from a large file ( aka mail store verify ) you will be essentially asking the filer to scan through it's blocks at a super high rate of speed.>>> #3 what happens to all other data that is stored on the same vol as the exchange DB once I defrag this vol? ie snap shots <<<The Mail store can be reallocated or the volume can. I would recommend the snapshots be removed as you can really get yourself into a pickle by 'RE'-writing a database with an application defrag, or a WAFL reallocate. If you are short on space, you need to get the snapshots out of there. Snapshots are locked images and if the file system is 'fragmented' then it is unlikely that you are doing much more than spinning your wheels if you are trying to defragment into a fragemnted snapshot. >>> #4 I ran a waffle scan and I got a reading of 1.8 si this fragmented? That is basically a ratio of actual file size ( df essentially ) to block allocation. Ex. A one terabyte volume has a 500 gig database. If it's layout is 1 then the File is essentially using the exact number of blocks that a Filer of 500 gigs needs. If the layout were 1.8 then the 500 gig df would still be 500 but the block allocation would actually be closer to the 900 gig . This is usually not an issue until the ratio takes the block allocation higher then the volume size. A 2.1 layout would mean that a 500 gig df would be 1.05 TB. This means you are rescanning on a request of data on the last .05 TB. If the Filer were a 900 gig df, then a layout of 1.8 would be MUCH more impactful. It is not the end of the world, you just have to manage it. You are on the right track I can see, so good luck. Thanks a bunch Skip Rich Borders

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RE: Best practices for new RAID group
by Yarmas, Tom 04 Jun '04

04 Jun '04

The paper you reference is a little dated unless you are still running 5.x of Data ONTAP. Data ONTAP version 6.x included some significant changes to the WAFL and ONTAP RAID. The number of RAID groups is much less relevant than the total number of data drives in the volume. However, adding 1 or two drives to a volume (or RAID Group) is still not the best approach. Your best bet is to add a new RAID group of 6 disks to the volume. You will be adding the disks anyway (over time), and you are using qtrees to divvy up the space, so just add them all at one time and not worry about it. As Chris Thompson pointed out you can use RAID-DP (assuming you are running DOT 6.5), and add 2 disks to the existing RAID group. But that would likely not be optimal because you would still have a small number of "empty" disks in the RAID group and they will be utilized more than the other "more full" disks until space gets more evenly distributed across all of the drives. -tom -----Original Message----- From: Stewart, John [mailto:johns@artesyncp.com] Sent: Thursday, June 03, 2004 5:44 PM To: 'toasters(a)mathworks.com' Cc: IT Technical Services Subject: Best practices for new RAID group We've got an F740 with three shelves of 36GB disks (the 3rd recently added). We've only got one volume, vol0, with 14 disks in it now (13 data and one parity). We use both CIFS and NFS. We have 7 spare disks (6 of which we'd like to eventually use for data, with one spare of course). I just went to add one of the spare disks to vol0 (running low on space) and got the error: vol add: starting a new RAID group; at least two disks are needed So, as I (now) understand it, we've got to either: - Override the 14 disk limit for a RAID group or - Add a new RAID group to the current volume or - Add a new volume The 3rd choice is unattractive because we like the idea of One Huge Filesystem, that we can divvy up as needed into different qtrees. The 2nd choice sounds like a Bad Idea in that according to this document, section 3.4: http://www.netapp.com/tech_library/3027.html, that the filer will try to distribute writes evenly between the old and new RAID group... if the new RAID group only contains two disks (we don't want to add more disk space than is needed now), this could be disatrous to performance So is the 1st choice, increasing the size of the RAID group, a viable option? What is the downsize? Only increased risk of a double disk failure taking out the whole system? Is it possible to add a second parity disk to the same RAID group? Am I missing something here? Any clue-by-fours quite welcome. thanks johnS

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RE: Best practices for new RAID group
by Derek Lai 04 Jun '04

04 Jun '04

The first option is not good either because the moment you increase the size of the raid group and add only 1 drive, all the new writes are going to that one drive until it catches up in space utilization as the rest of the drives in that raid group. Performance will come to a screeching halt. So NetApp definitely will let you do it but at the risk of really bad performance. The only way I would do this is to back up everything, blow the volume away, create the volume again with all the drives and then restore the data. NetApp typically suggest you add at least a few drives at a time. Sorry. Derek -----Original Message----- From: Stewart, John [mailto:johns@artesyncp.com] Sent: Thursday, June 03, 2004 2:44 PM To: 'toasters(a)mathworks.com' Cc: IT Technical Services Subject: Best practices for new RAID group We've got an F740 with three shelves of 36GB disks (the 3rd recently added). We've only got one volume, vol0, with 14 disks in it now (13 data and one parity). We use both CIFS and NFS. We have 7 spare disks (6 of which we'd like to eventually use for data, with one spare of course). I just went to add one of the spare disks to vol0 (running low on space) and got the error: vol add: starting a new RAID group; at least two disks are needed So, as I (now) understand it, we've got to either: - Override the 14 disk limit for a RAID group or - Add a new RAID group to the current volume or - Add a new volume The 3rd choice is unattractive because we like the idea of One Huge Filesystem, that we can divvy up as needed into different qtrees. The 2nd choice sounds like a Bad Idea in that according to this document, section 3.4: http://www.netapp.com/tech_library/3027.html, that the filer will try to distribute writes evenly between the old and new RAID group... if the new RAID group only contains two disks (we don't want to add more disk space than is needed now), this could be disatrous to performance So is the 1st choice, increasing the size of the RAID group, a viable option? What is the downsize? Only increased risk of a double disk failure taking out the whole system? Is it possible to add a second parity disk to the same RAID group? Am I missing something here? Any clue-by-fours quite welcome. thanks johnS

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Best practices for new RAID group
by Stewart, John 03 Jun '04

03 Jun '04

We've got an F740 with three shelves of 36GB disks (the 3rd recently added). We've only got one volume, vol0, with 14 disks in it now (13 data and one parity). We use both CIFS and NFS. We have 7 spare disks (6 of which we'd like to eventually use for data, with one spare of course). I just went to add one of the spare disks to vol0 (running low on space) and got the error: vol add: starting a new RAID group; at least two disks are needed So, as I (now) understand it, we've got to either: - Override the 14 disk limit for a RAID group or - Add a new RAID group to the current volume or - Add a new volume The 3rd choice is unattractive because we like the idea of One Huge Filesystem, that we can divvy up as needed into different qtrees. The 2nd choice sounds like a Bad Idea in that according to this document, section 3.4: http://www.netapp.com/tech_library/3027.html, that the filer will try to distribute writes evenly between the old and new RAID group... if the new RAID group only contains two disks (we don't want to add more disk space than is needed now), this could be disatrous to performance So is the 1st choice, increasing the size of the RAID group, a viable option? What is the downsize? Only increased risk of a double disk failure taking out the whole system? Is it possible to add a second parity disk to the same RAID group? Am I missing something here? Any clue-by-fours quite welcome. thanks johnS

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