Hi all,
We have a ton of shelves with 320gb sata in them. We'd like to replace them with 1tb satas, but we have no power to power new shelves, or much space for them for that matter.
I know that if I swap out one 320gb disk with a 1tb one, the netapp will only use 320gb of the 1tb disk. But if I did all 14, one at a time so it syncs, what happens after I change the 14th disk? Will the netapp still only use 320gb per disk, or will it realise it has a whole 1tb to play with?
Peta
I have tried and tested every possible permutation of trying to replace small disks in a RAID group (or aggregate) with larger ones.
Though there seems to be promising looking methods that appear to stand a chance of working they will not. It cannot be done.
Graham
-----Original Message----- From: Peta Spies [mailto:peta.spies@gmail.com] Sent: Monday, December 01, 2008 11:11 AM To: toasters@mathworks.com Subject: Crazy disk swap thought
Hi all,
We have a ton of shelves with 320gb sata in them. We'd like to replace them with 1tb satas, but we have no power to power new shelves, or much space for them for that matter.
I know that if I swap out one 320gb disk with a 1tb one, the netapp will only use 320gb of the 1tb disk. But if I did all 14, one at a time so it syncs, what happens after I change the 14th disk? Will the netapp still only use 320gb per disk, or will it realise it has a whole 1tb to play with?
Peta
Unless NTAP changes the code, if you swap any disk for a larger size disk, the larger size disk becomes the same size of the disk it replaced and you cannot recoup the extra space.
Find yourself a way to get temp power...even if that means running a few pieces of equipment on half of their power supplies (just don't overload the circuit)!.
--tmac
RedHat Certified Engineer #804006984323821 (RHEL4) RedHat Certified Engineer #805007643429572 (RHEL5)
Principal Consultant
On Mon, Dec 1, 2008 at 1:10 PM, Peta Spies peta.spies@gmail.com wrote:
Hi all,
We have a ton of shelves with 320gb sata in them. We'd like to replace them with 1tb satas, but we have no power to power new shelves, or much space for them for that matter.
I know that if I swap out one 320gb disk with a 1tb one, the netapp will only use 320gb of the 1tb disk. But if I did all 14, one at a time so it syncs, what happens after I change the 14th disk? Will the netapp still only use 320gb per disk, or will it realise it has a whole 1tb to play with?
Peta
It wouldn't be a matter of the number of disks in a shelf, but the raid group size and number of disks in the aggregate. Even if it would work, you would end up with wasted disk space as the largest aggregate you can have is 16TB. With 320GB disks, that would be roughly 56 disks, with 1TB disks, it would only be 16. So, if you have more than 16 disks in your current aggregate, you would exceed your max aggregate capacity after 16 1TB disks if the filer were to see them as 1TB disks.
----- Original Message ----- From: "Peta Spies" peta.spies@gmail.com To: toasters@mathworks.com Sent: Monday, December 01, 2008 1:10 PM Subject: Crazy disk swap thought
Hi all,
We have a ton of shelves with 320gb sata in them. We'd like to replace them with 1tb satas, but we have no power to power new shelves, or much space for them for that matter.
I know that if I swap out one 320gb disk with a 1tb one, the netapp will only use 320gb of the 1tb disk. But if I did all 14, one at a time so it syncs, what happens after I change the 14th disk? Will the netapp still only use 320gb per disk, or will it realise it has a whole 1tb to play with?
Peta
On 1 Dec 2008, at 20:14, Bill Holland wrote:
It wouldn't be a matter of the number of disks in a shelf, but the raid group size and number of disks in the aggregate. Even if it would work, you would end up with wasted disk space as the largest aggregate you can have is 16TB. With 320GB disks, that would be roughly 56 disks, with 1TB disks, it would only be 16. So, if you have more than 16 disks in your current aggrate, you would exceed your max aggregate capacity after 16 1TB disks if the filer were to see them as 1TB disks.
As an aside isn't it the maximum size of the aggregate the cooked size rather than the raw, so isn't it around 19 disks ( there is an option which I am not sure is documented to raise the maximum group size ).
This is from a netapp pre-sales person.
Storage system
Minimum group size
Maximum group size
Default group size
All storage systems (with SATA disks)
3
16
14
All storage systems (with FC disks)
3
28
16
1TB SATA = 10,615GB – max 19 disks per aggregate based on 1 spare and two RAID sets of 8+2 and 7+2 This means you can get about 105TB of real space out of a cabinet of 1TB drives versus about 85TB for the next drive size down, 750GB drives
The option you suggested of a single RAID set per aggregate is not supported as this would require 19 disks in the RAID set. 12,030GB = max 19 disks – 1 x 17+2 (unsupported)
It depends on the version of OnTap you are running. Prior to 7.3 it was based on raw size. As of 7.3 it's cooked size.
There's a nice chart in the 7.3 release notes under 'Storage resource management enchancements' showing all this.
On Mon, Dec 01, 2008 at 08:25:01PM +0000, James Beal wrote:
On 1 Dec 2008, at 20:14, Bill Holland wrote:
It wouldn't be a matter of the number of disks in a shelf, but the raid group size and number of disks in the aggregate. Even if it would work, you would end up with wasted disk space as the largest aggregate you can have is 16TB. With 320GB disks, that would be roughly 56 disks, with 1TB disks, it would only be 16. So, if you have more than 16 disks in your current aggrate, you would exceed your max aggregate capacity after 16 1TB disks if the filer were to see them as 1TB disks.
As an aside isn't it the maximum size of the aggregate the cooked size rather than the raw, so isn't it around 19 disks ( there is an option which I am not sure is documented to raise the maximum group size ).
This is from a netapp pre-sales person.
Storage system
Minimum group size
Maximum group size
Default group size
All storage systems (with SATA disks)
3
16
14
All storage systems (with FC disks)
3
28
16
1TB SATA = 10,615GB ? max 19 disks per aggregate based on 1 spare and two RAID sets of 8+2 and 7+2 This means you can get about 105TB of real space out of a cabinet of 1TB drives versus about 85TB for the next drive size down, 750GB drives
The option you suggested of a single RAID set per aggregate is not supported as this would require 19 disks in the RAID set. 12,030GB = max 19 disks ? 1 x 17+2 (unsupported)
This is a relatively recent development....I think with 7.2.5 or 7.3 possibly.
Glenn Dekhayser VoyantStrategies
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of James Beal Sent: Monday, December 01, 2008 3:25 PM To: Bill Holland Cc: Peta Spies; toasters@mathworks.com Subject: Re: Crazy disk swap thought
On 1 Dec 2008, at 20:14, Bill Holland wrote:
It wouldn't be a matter of the number of disks in a shelf, but the raid group size and number of disks in the aggregate. Even if it would work, you would end up with wasted disk space as the largest aggregate you can have is 16TB. With 320GB disks, that would be roughly 56 disks, with 1TB disks, it would only be 16. So, if you have more than 16 disks in your current aggrate, you would exceed your max aggregate capacity after 16 1TB disks if the filer were to see them as 1TB disks.
As an aside isn't it the maximum size of the aggregate the cooked size rather than the raw, so isn't it around 19 disks ( there is an option which I am not sure is documented to raise the maximum group size ).
This is from a netapp pre-sales person.
Storage system
Minimum group size
Maximum group size
Default group size
All storage systems (with SATA disks)
3
16
14
All storage systems (with FC disks)
3
28
16
1TB SATA = 10,615GB - max 19 disks per aggregate based on 1 spare and two RAID sets of 8+2 and 7+2 This means you can get about 105TB of real space out of a cabinet of 1TB drives versus about 85TB for the next drive size down, 750GB drives
The option you suggested of a single RAID set per aggregate is not supported as this would require 19 disks in the RAID set. 12,030GB = max 19 disks - 1 x 17+2 (unsupported)
-
Bill Holland -
Glenn Dekhayser -
James Beal -
Jeff Bryer -
Knight, Graham -
Peta Spies -
tmac