toasters January 2007

toasters@lists.teaparty.net

62 participants
76 discussions

RE: Aggregate expansion
by Ledbetter, Jason 22 Jan '07

22 Jan '07

Moving from 14->56, no. WAFL does not immediately go and lay out the original data again across all disks. As such, initially new writes should get spread across all of these disks. Thus, one might see a read difference in the near-term that would smooth out over time (IOW, reads from the 'old' 14 disks can only come from those 14 disks.. whereas new reads can come from all 56 disks). (To Rich's point, if you say, went from 56 to 60 disks, the possibility for new writes to go to just the 4 disks for a period of time exists as WAFL "levels" itself out over time.. that would be "hot" disks.) Hope this helps. -jbl -----Original Message----- From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] Sent: Monday, January 22, 2007 2:29 PM To: Borders, Rich; toasters(a)mathworks.com Subject: RE: Aggregate expansion I mean with existing data on the aggregate. To clarify, say I first create an aggregate with 14 disks (and default raid size). Then this aggregate is populated with data. After a period of time the aggregate is expanded by adding disks, say to 56 disks. The question is, is there a difference (in performance, efficiency) between the aggregate as described above and an aggregate that was originally created from all 56 disks? Suresh -----Original Message----- From: Borders, Rich [mailto:Rich.Borders@netapp.com] Sent: Monday, January 22, 2007 11:25 AM To: Suresh Rajagopalan; toasters(a)mathworks.com Subject: RE: Aggregate expansion Yes... You can make hot disks happen. Do you mean without adding any data? Richard D Borders CPR Escalations Engineer RTP, North Carolina USA - Network Appliance, Inc. Email: rborders(a)netapp.com Phone:(919) 476-5236 Cell: (919) 606-5099 Fax: (919) 476-5608 > -----Original Message----- > From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] > Sent: Monday, January 22, 2007 12:46 PM > To: toasters(a)mathworks.com > Subject: Aggregate expansion > > Is there any difference between creating an aggregate on a certain > number of disks (say n) , and then later expanding the aggregate to N > disks, as opposed to creating the initial aggregate on N disks? > > > > Suresh > >

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RE: Aggregate expansion
by Fox, Adam 22 Jan '07

22 Jan '07

That depends greatly on the values of N and n, as well as the RAID group size of the aggregate. Done according to best practices, there will be almost no difference. Done poorly, it can make all the difference in the world. My personal view (I'm in no position to speak officially for NetApp) on this to add disks to an aggregate in one of 2 multiples: 1) a whole RG at a time 2) half a RG at a time. This typically allows for a sufficient number of free disks such that you should not expect any noticable performance difference. I realize that not all sites can implement this, but let's look at a worst practice: N = n+1 Fill up the aggregate, then add 1 disk. Ouch! This hurts! So you've seen what I consider to be the best case for adding space, and you've seen the worst case. So how close you are to these extremes should give you can idea of what to expect. I know this isn't a simple answer, but I believe it to be accruate. -- Adam Fox adamfox(a)netapp.com _____ From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] Sent: Monday, January 22, 2007 12:46 PM To: toasters(a)mathworks.com Subject: Aggregate expansion Is there any difference between creating an aggregate on a certain number of disks (say n) , and then later expanding the aggregate to N disks, as opposed to creating the initial aggregate on N disks? Suresh

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RE: Aggregate expansion
by Suresh Rajagopalan 22 Jan '07

22 Jan '07

I mean with existing data on the aggregate. To clarify, say I first create an aggregate with 14 disks (and default raid size). Then this aggregate is populated with data. After a period of time the aggregate is expanded by adding disks, say to 56 disks. The question is, is there a difference (in performance, efficiency) between the aggregate as described above and an aggregate that was originally created from all 56 disks? Suresh -----Original Message----- From: Borders, Rich [mailto:Rich.Borders@netapp.com] Sent: Monday, January 22, 2007 11:25 AM To: Suresh Rajagopalan; toasters(a)mathworks.com Subject: RE: Aggregate expansion Yes... You can make hot disks happen. Do you mean without adding any data? Richard D Borders CPR Escalations Engineer RTP, North Carolina USA - Network Appliance, Inc. Email: rborders(a)netapp.com Phone:(919) 476-5236 Cell: (919) 606-5099 Fax: (919) 476-5608 > -----Original Message----- > From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] > Sent: Monday, January 22, 2007 12:46 PM > To: toasters(a)mathworks.com > Subject: Aggregate expansion > > Is there any difference between creating an aggregate on a certain > number of disks (say n) , and then later expanding the aggregate to N > disks, as opposed to creating the initial aggregate on N disks? > > > > Suresh > >

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Aggregate expansion
by Suresh Rajagopalan 22 Jan '07

22 Jan '07

Is there any difference between creating an aggregate on a certain number of disks (say n) , and then later expanding the aggregate to N disks, as opposed to creating the initial aggregate on N disks? Suresh

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RE: Aggregate expansion
by Borders, Rich 22 Jan '07

22 Jan '07

Yes... You can make hot disks happen. Do you mean without adding any data? Richard D Borders CPR Escalations Engineer RTP, North Carolina USA - Network Appliance, Inc. Email: rborders(a)netapp.com Phone:(919) 476-5236 Cell: (919) 606-5099 Fax: (919) 476-5608 > -----Original Message----- > From: Suresh Rajagopalan [mailto:SRajagopalan@williamoneil.com] > Sent: Monday, January 22, 2007 12:46 PM > To: toasters(a)mathworks.com > Subject: Aggregate expansion > > Is there any difference between creating an aggregate on a certain > number of disks (say n) , and then later expanding the aggregate to N > disks, as opposed to creating the initial aggregate on N disks? > > > > Suresh > >

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RE: Snapvault question
by Glenn Walker 19 Jan '07

19 Jan '07

This may help: http://now.netapp.com/Knowledgebase/solutionarea.asp?id=kb19470 Glenn ________________________________ From: Glenn Walker Sent: Thursday, January 18, 2007 4:36 PM To: Glenn Walker; 'Owens, Jeff'; 'toasters(a)mathworks.com' Subject: RE: Snapvault question To clarify this further: I _believe_ you can make use of VSM, then implement QSM\SV, but you would end up losing the existing snapvault relationships. I'm not so sure the LREP is much of an improvement on this. I hope I'm wrong. Glenn ________________________________ From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Glenn Walker Sent: Thursday, January 18, 2007 4:13 PM To: Owens, Jeff; toasters(a)mathworks.com Subject: RE: Snapvault question The only way I know of doing a baseline snapshot with QSM\SnapVault would be utilizing LREP. There are no snapshots at all in common?? Glenn ________________________________ From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Owens, Jeff Sent: Thursday, January 18, 2007 3:20 PM To: toasters(a)mathworks.com Subject: Snapvault question Question for you guys. I am snapvaulting data from a couple of FAS940's over to an R200. I have lost one of my baseline snapshots on the primary filer and am unable to resync that snapvault since there is no baseline snapshot to reference from. Is there any way to create another baseline snapshot ? Jeff

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RE: Snapvault question
by Glenn Walker 18 Jan '07

18 Jan '07

To clarify this further: I _believe_ you can make use of VSM, then implement QSM\SV, but you would end up losing the existing snapvault relationships. I'm not so sure the LREP is much of an improvement on this. I hope I'm wrong. Glenn ________________________________ From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Glenn Walker Sent: Thursday, January 18, 2007 4:13 PM To: Owens, Jeff; toasters(a)mathworks.com Subject: RE: Snapvault question The only way I know of doing a baseline snapshot with QSM\SnapVault would be utilizing LREP. There are no snapshots at all in common?? Glenn ________________________________ From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Owens, Jeff Sent: Thursday, January 18, 2007 3:20 PM To: toasters(a)mathworks.com Subject: Snapvault question Question for you guys. I am snapvaulting data from a couple of FAS940's over to an R200. I have lost one of my baseline snapshots on the primary filer and am unable to resync that snapvault since there is no baseline snapshot to reference from. Is there any way to create another baseline snapshot ? Jeff

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RE: Snapvault question
by Glenn Walker 18 Jan '07

18 Jan '07

The only way I know of doing a baseline snapshot with QSM\SnapVault would be utilizing LREP. There are no snapshots at all in common?? Glenn ________________________________ From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Owens, Jeff Sent: Thursday, January 18, 2007 3:20 PM To: toasters(a)mathworks.com Subject: Snapvault question Question for you guys. I am snapvaulting data from a couple of FAS940's over to an R200. I have lost one of my baseline snapshots on the primary filer and am unable to resync that snapvault since there is no baseline snapshot to reference from. Is there any way to create another baseline snapshot ? Jeff

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Snapvault question
by Owens, Jeff 18 Jan '07

18 Jan '07

Question for you guys. I am snapvaulting data from a couple of FAS940's over to an R200. I have lost one of my baseline snapshots on the primary filer and am unable to resync that snapvault since there is no baseline snapshot to reference from. Is there any way to create another baseline snapshot ? Jeff

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Oracle Replication & Snapshot-space Queries
by Raj Patel 18 Jan '07

18 Jan '07

Hi, Couple of quick queries - 1. In terms of Oracle data replication - is it worth using low level data replication to another SAN (eg using NetApps tools) or do it via Oracle itself ? Which is 'safer' / 'faster' ? Whats the bandwidth requirement comparison for SAN replication vs database replication ? 2. What sort of space utilisation do people 'allocate' for their snapshot cycle ? Vendors quote storage space and snapshot functionality but seem to gloss over the fact that snapshots eat into the SAN's available space. Thanks in advance, Raj.

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toasters January 2007