When the stripes fill the equivalent of the smaller disks, wafl will start striping only on the larger disks. This will cause performance degradation due to "hot" disks.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of David Knight Sent: Thursday, September 21, 2006 9:44 AM To: ggwalker@mindspring.com Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: Re: Mixed disk sizes within a single aggregate
I think wafl stripes across all disks in an aggregate. I'm not sure how it respond to having one raid group with larger disks - likely it will not use part of them. I'm pretty sure netapp recommends all disks in an aggregate be the same size, or, it will assume they are all the size of the smallest disk. Of course, I could be wrong . . .
David
Remember that WAFL still writes across the entire aggregate. Having a
slower RAID group in an aggregate of faster raid groups would be akin to having a slower disk in a RG of faster disks, would it not?
Glenn
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Brosseau, Paul Sent: Wednesday, September 20, 2006 8:05 PM To: Jeff Mery; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
Mixing disk sizes in an aggregate is not a problem as long as you create RAID groups for each kind of disk. WAFL creates stripes at the
RAID group level. For best results create complete RAID groups each time you add disks to an aggregate.
Paulb
From: Jeff Mery [mailto:jeff.mery@ni.com] Sent: Wednesday, September 20, 2006 3:30 PM To: toasters@mathworks.com Subject: Mixed disk sizes within a single aggregate
Greetings fellow toasters!
<Background> We're looking at moving our 2 FAS940 systems from tradtional volumes to flexvols + aggregates. </Background>
It would seem to me that the same rules and guidelines for creating traditional volumes now apply directly to the aggregate level (for the
most part). By rules and guidelines I mean things like trying not to mix disk sizes, try to avoid volumes (now aggregates?) that span FC adapters, etc.
Are any of these things still a concern on modern versions of ONTAP (7+)? Does anyone have any best practices they'd be willing to share in regards to aggregate creation? NOW says "make them as big as possible using as many spindles as possible", but that doesn't really
help much.
We use our filers for unstructured data only; cifs + nfs but no databases, no snapmirror, no snapvault, etc..
TIA, Jeff Mery - MCSE, MCP National Instruments
--
"Allow me to extol the virtues of the Net Fairy, and of all the fantastic dorks that make the nice packets go from here to there. Amen." TB - Penny Arcade
--
Confidentiality Notice: This e-mail is intended only for the personal and confidential use of the individual to whom it is addressed and may contain information that is privileged, confidential and protected by law. If you are not the intended recipient, you are hereby notified that any use or disclosure of this information is strictly prohibited. If you have received this message in error, please notify the sender immediately by reply e-mail and delete the original message. Your compliance is appreciated.
Exactly :)
Consistency is key: always try to keep same disk sizes speeds in aggregates. I'd feel more comfortable adding disks with faster speeds than larger sizes - there will be no future performance degradation from this.
Glenn
-----Original Message----- From: Crawford, Mark (CBC) [mailto:Mark.Crawford@CapBlueCross.COM] Sent: Thu 9/21/2006 10:53 AM To: David Knight; Glenn Walker Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
When the stripes fill the equivalent of the smaller disks, wafl will start striping only on the larger disks. This will cause performance degradation due to "hot" disks.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of David Knight Sent: Thursday, September 21, 2006 9:44 AM To: ggwalker@mindspring.com Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: Re: Mixed disk sizes within a single aggregate
I think wafl stripes across all disks in an aggregate. I'm not sure how it respond to having one raid group with larger disks - likely it will not use part of them. I'm pretty sure netapp recommends all disks in an aggregate be the same size, or, it will assume they are all the size of the smallest disk. Of course, I could be wrong . . .
David
Remember that WAFL still writes across the entire aggregate. Having a
slower RAID group in an aggregate of faster raid groups would be akin to having a slower disk in a RG of faster disks, would it not?
Glenn
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Brosseau, Paul Sent: Wednesday, September 20, 2006 8:05 PM To: Jeff Mery; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
Mixing disk sizes in an aggregate is not a problem as long as you create RAID groups for each kind of disk. WAFL creates stripes at the
RAID group level. For best results create complete RAID groups each time you add disks to an aggregate.
Paulb
From: Jeff Mery [mailto:jeff.mery@ni.com] Sent: Wednesday, September 20, 2006 3:30 PM To: toasters@mathworks.com Subject: Mixed disk sizes within a single aggregate
Greetings fellow toasters!
<Background> We're looking at moving our 2 FAS940 systems from tradtional volumes to flexvols + aggregates. </Background>
It would seem to me that the same rules and guidelines for creating traditional volumes now apply directly to the aggregate level (for the
most part). By rules and guidelines I mean things like trying not to mix disk sizes, try to avoid volumes (now aggregates?) that span FC adapters, etc.
Are any of these things still a concern on modern versions of ONTAP (7+)? Does anyone have any best practices they'd be willing to share in regards to aggregate creation? NOW says "make them as big as possible using as many spindles as possible", but that doesn't really
help much.
We use our filers for unstructured data only; cifs + nfs but no databases, no snapmirror, no snapvault, etc..
TIA, Jeff Mery - MCSE, MCP National Instruments
--
"Allow me to extol the virtues of the Net Fairy, and of all the fantastic dorks that make the nice packets go from here to there. Amen." TB - Penny Arcade
--
Confidentiality Notice: This e-mail is intended only for the personal and confidential use of the individual to whom it is addressed and may contain information that is privileged, confidential and protected by law. If you are not the intended recipient, you are hereby notified that any use or disclosure of this information is strictly prohibited. If you have received this message in error, please notify the sender immediately by reply e-mail and delete the original message. Your compliance is appreciated.
I always thought you would have problems mixing speeds in a raid group. Specifically you would see 'failing servo motor' autosupport messages.
Or are you suggesting raid groups segregated by speed and only mixing speeds within an aggregate made up of the speed based raid groups?
-Matthew
On Thu, September 21, 2006 11:01 am, Glenn Walker wrote:
Exactly :)
Consistency is key: always try to keep same disk sizes speeds in aggregates. I'd feel more comfortable adding disks with faster speeds than larger sizes - there will be no future performance degradation from this.
Glenn
-----Original Message----- From: Crawford, Mark (CBC) [mailto:Mark.Crawford@CapBlueCross.COM] Sent: Thu 9/21/2006 10:53 AM To: David Knight; Glenn Walker Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
When the stripes fill the equivalent of the smaller disks, wafl will start striping only on the larger disks. This will cause performance degradation due to "hot" disks.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of David Knight Sent: Thursday, September 21, 2006 9:44 AM To: ggwalker@mindspring.com Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: Re: Mixed disk sizes within a single aggregate
I think wafl stripes across all disks in an aggregate. I'm not sure how it respond to having one raid group with larger disks - likely it will not use part of them. I'm pretty sure netapp recommends all disks in an aggregate be the same size, or, it will assume they are all the size of the smallest disk. Of course, I could be wrong . . .
David
Remember that WAFL still writes across the entire aggregate. Having a
slower RAID group in an aggregate of faster raid groups would be akin to having a slower disk in a RG of faster disks, would it not?
Glenn
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Brosseau, Paul Sent: Wednesday, September 20, 2006 8:05 PM To: Jeff Mery; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
Mixing disk sizes in an aggregate is not a problem as long as you create RAID groups for each kind of disk. WAFL creates stripes at the
RAID group level. For best results create complete RAID groups each time you add disks to an aggregate.
Paulb
From: Jeff Mery [mailto:jeff.mery@ni.com] Sent: Wednesday, September 20, 2006 3:30 PM To: toasters@mathworks.com Subject: Mixed disk sizes within a single aggregate
Greetings fellow toasters!
<Background> We're looking at moving our 2 FAS940 systems from tradtional volumes to flexvols + aggregates. </Background>
It would seem to me that the same rules and guidelines for creating traditional volumes now apply directly to the aggregate level (for the
most part). By rules and guidelines I mean things like trying not to mix disk sizes, try to avoid volumes (now aggregates?) that span FC adapters, etc.
Are any of these things still a concern on modern versions of ONTAP (7+)? Does anyone have any best practices they'd be willing to share in regards to aggregate creation? NOW says "make them as big as possible using as many spindles as possible", but that doesn't really
help much.
We use our filers for unstructured data only; cifs + nfs but no databases, no snapmirror, no snapvault, etc..
TIA, Jeff Mery - MCSE, MCP National Instruments
--
"Allow me to extol the virtues of the Net Fairy, and of all the fantastic dorks that make the nice packets go from here to there. Amen." TB - Penny Arcade
--
Confidentiality Notice: This e-mail is intended only for the personal and confidential use of the individual to whom it is addressed and may contain information that is privileged, confidential and protected by law. If you are not the intended recipient, you are hereby notified that any use or disclosure of this information is strictly prohibited. If you have received this message in error, please notify the sender immediately by reply e-mail and delete the original message. Your compliance is appreciated.
I always thought you would have problems mixing speeds in a raid group. Specifically you would see 'failing servo motor' autosupport messages.
Or are you suggesting raid groups segregated by speed and only mixing speeds within an aggregate made up of the speed based raid groups?
-Matthew
On our R200 the original 320G drives are 5400 RPM. We recently bought two more shelves and these were all 7200 RPM. Since then some 5400 RPM drives have failed and the system has reconstructed on 5400 RPM hot spares. The replacements from Netapp have all been 7200 RPM, so we have no 5400 RPM hot spares any more. We'll find out if mixed speed raid groups work when the next 5400 RPM disk dies :-)
Actually Netapp told us it's not a problem to replace a slower drive with a faster one. It's not good if you have a RG of fast drives to replace one with a slower drive, because that drags down the whole RG.
Steve Losen scl@virginia.edu phone: 434-924-0640
University of Virginia ITC Unix Support
Actually Netapp told us it's not a problem to replace a slower drive with a faster one. It's not good if you have a RG of fast drives to replace one with a slower drive, because that drags down the whole RG.
Yeah a read would have to wait for the slower disk to spin around to the proper block while all the faster disks have already provided the data.
-Matthew
A "Failing servo motor" message shouldn't have anything to do with mixing drive speeds. That's just a bad disk.
-Blake
On 9/21/06, maclean@cs.mcgill.ca maclean@cs.mcgill.ca wrote:
I always thought you would have problems mixing speeds in a raid group. Specifically you would see 'failing servo motor' autosupport messages.
Or are you suggesting raid groups segregated by speed and only mixing speeds within an aggregate made up of the speed based raid groups?
-Matthew
On Thu, September 21, 2006 11:01 am, Glenn Walker wrote:
Exactly :)
Consistency is key: always try to keep same disk sizes speeds in aggregates. I'd feel more comfortable adding disks with faster speeds than larger sizes - there will be no future performance degradation from this.
Glenn
-----Original Message----- From: Crawford, Mark (CBC) [mailto:Mark.Crawford@CapBlueCross.COM] Sent: Thu 9/21/2006 10:53 AM To: David Knight; Glenn Walker Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
When the stripes fill the equivalent of the smaller disks, wafl will start striping only on the larger disks. This will cause performance degradation due to "hot" disks.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of David Knight Sent: Thursday, September 21, 2006 9:44 AM To: ggwalker@mindspring.com Cc: Paul.Brosseau@netapp.com; jeff.mery@ni.com; toasters@mathworks.com Subject: Re: Mixed disk sizes within a single aggregate
I think wafl stripes across all disks in an aggregate. I'm not sure how it respond to having one raid group with larger disks - likely it will not use part of them. I'm pretty sure netapp recommends all disks in an aggregate be the same size, or, it will assume they are all the size of the smallest disk. Of course, I could be wrong . . .
David
Remember that WAFL still writes across the entire aggregate. Having a
slower RAID group in an aggregate of faster raid groups would be akin to having a slower disk in a RG of faster disks, would it not?
Glenn
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Brosseau, Paul Sent: Wednesday, September 20, 2006 8:05 PM To: Jeff Mery; toasters@mathworks.com Subject: RE: Mixed disk sizes within a single aggregate
Mixing disk sizes in an aggregate is not a problem as long as you create RAID groups for each kind of disk. WAFL creates stripes at the
RAID group level. For best results create complete RAID groups each time you add disks to an aggregate.
Paulb
From: Jeff Mery [mailto:jeff.mery@ni.com] Sent: Wednesday, September 20, 2006 3:30 PM To: toasters@mathworks.com Subject: Mixed disk sizes within a single aggregate
Greetings fellow toasters!
<Background> We're looking at moving our 2 FAS940 systems from tradtional volumes to flexvols + aggregates. </Background>
It would seem to me that the same rules and guidelines for creating traditional volumes now apply directly to the aggregate level (for the
most part). By rules and guidelines I mean things like trying not to mix disk sizes, try to avoid volumes (now aggregates?) that span FC adapters, etc.
Are any of these things still a concern on modern versions of ONTAP (7+)? Does anyone have any best practices they'd be willing to share in regards to aggregate creation? NOW says "make them as big as possible using as many spindles as possible", but that doesn't really
help much.
We use our filers for unstructured data only; cifs + nfs but no databases, no snapmirror, no snapvault, etc..
TIA, Jeff Mery - MCSE, MCP National Instruments
--
"Allow me to extol the virtues of the Net Fairy, and of all the fantastic dorks that make the nice packets go from here to there. Amen." TB - Penny Arcade
--
Confidentiality Notice: This e-mail is intended only for the personal and confidential use of the individual to whom it is addressed and may contain information that is privileged, confidential and protected by law. If you are not the intended recipient, you are hereby notified that any use or disclosure of this information is strictly prohibited. If you have received this message in error, please notify the sender immediately by reply e-mail and delete the original message. Your compliance is appreciated.
-
Blake Golliher -
Crawford, Mark (CBC) -
Glenn Walker -
maclean＠cs.mcgill.ca -
Stephen C. Losen