Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
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Why not break the mirror change the minra setting and give it a go? You should know pretty quickly if it makes any difference. Our backup config is the same as yours, and we have a couple of volumes with millions of files that are also slow to backup.
- Carl ________________________________
From: owner-toasters@mathworks.com on behalf of Peter D. Gray Sent: Thu 8/31/2006 6:53 PM To: toasters@mathworks.com Subject: Re: when to use minra ?
Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
--
See mail headers for contact information.
Only option is to change the minra on the source since vol options cannot change in snapmirror destinations. If you really worried changing minra in a peak time, you can try changing minra in a non peak time and let the change snapmirror to destination volume in R200. Then try taking backup's off from that volume. (just to isolate)
Seems like minra is not the only cause for your case. can you provide more details on your appliances? Model's, disk size's, aggregates & volume sizes in both source & destination. Also the details of your tape library attached to R200. ( believe it's directly attached to R200)
Brian.
"Carl Howell" chowell@uwf.edu To: "Peter D. Gray" pdg@uow.edu.au, toasters@mathworks.com Sent by: cc: owner-toasters@ma Subject: RE: when to use minra ? thworks.com
09/01/2006 08:28 AM
Why not break the mirror change the minra setting and give it a go? You should know pretty quickly if it makes any difference. Our backup config is the same as yours, and we have a couple of volumes with millions of files that are also slow to backup.
- Carl ________________________________
From: owner-toasters@mathworks.com on behalf of Peter D. Gray Sent: Thu 8/31/2006 6:53 PM To: toasters@mathworks.com Subject: Re: when to use minra ?
Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
--
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I admit that I never thought of this case. Nevertheless, as far as I remember, the new caching algorithms in 6.5.x/7.x should be dynamic enough to cover up for this - maybe the reason your backup is slow is unrelated. Have you tried to collect a PerfStat output and analyze it yourself or with another person that is capable of reading its output? Have you tried to dump to null to see if that is faster? There have been improvements in dump speeds across releases...
Eyal.
On 8/31/06, Carl Howell < chowell@uwf.edu> wrote:
Why not break the mirror change the minra setting and give it a go? You should know pretty quickly if it makes any difference. Our backup config is the same as yours, and we have a couple of volumes with millions of files that are also slow to backup.
- Carl
From: owner-toasters@mathworks.com on behalf of Peter D. Gray Sent: Thu 8/31/2006 6:53 PM To: toasters@mathworks.com Subject: Re: when to use minra ?
Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
--
See mail headers for contact information.
Some of the dynamic read ahead stuff isn't so great in the real world. Especially with email and small files. It seems to be mostly designed with luns / oracle data files in mind. And even then a large enough database with suitably small and random reads usually make minra turned to on a necessity.
-Blake
On 8/31/06, Eyal Traitel etraitel@gmail.com wrote:
I admit that I never thought of this case. Nevertheless, as far as I remember, the new caching algorithms in 6.5.x/7.x should be dynamic enough to cover up for this - maybe the reason your backup is slow is unrelated. Have you tried to collect a PerfStat output and analyze it yourself or with another person that is capable of reading its output? Have you tried to dump to null to see if that is faster? There have been improvements in dump speeds across releases...
Eyal.
On 8/31/06, Carl Howell < chowell@uwf.edu> wrote:
Why not break the mirror change the minra setting and give it a go? You
should know pretty quickly if it makes any difference. Our backup config is the same as yours, and we have a couple of volumes with millions of files that are also slow to backup.
- Carl
From: owner-toasters@mathworks.com on behalf of Peter D. Gray Sent: Thu 8/31/2006 6:53 PM To: toasters@mathworks.com Subject: Re: when to use minra ?
Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
--
See mail headers for contact information.
-- Yours, Eyal.
Have you looked into Snapmirror to tape for your backups? You lose on incrementials, but that may not be a big deal for you. It's a block level backup of the entire volume. Might help speed things up.
-Blake
On 8/31/06, Carl Howell chowell@uwf.edu wrote:
Why not break the mirror change the minra setting and give it a go? You should know pretty quickly if it makes any difference. Our backup config is the same as yours, and we have a couple of volumes with millions of files that are also slow to backup.
- Carl
From: owner-toasters@mathworks.com on behalf of Peter D. Gray Sent: Thu 8/31/2006 6:53 PM To: toasters@mathworks.com Subject: Re: when to use minra ?
Thanks for the replies. Some background on this question.
I have 2 filers used for email storage (NFS, attached to 2 mirapoint mail stores). They have lots of small files. I am mirroring these 2 filers to an R200 for backup, but I also take tape copies via NDMP every 30 days or so. The volumes contain about 350GB each of actual data, excluding snapshots, and 5 million files.
My NDMP tape backups from the R200 are pretty slow. I average about 2 MBytes per sec. Note that backups of other volumes on te R200 work really well, so there is no problem on the R200 or the network.
I saw the comment that turning off minra can have a big impact on backup performance so I thought I would try it. But discovered that the setting would have to be changed on the mirror source which is not so good (maybe).
It would be nice if that setting could be changed on the mirror target but not the source, but I can see why that not possible.
So, I wondered if I could justify setting minra on on the source volumes but would need some way to predict the impact.
It sounds like turing on minra is not usually a good idea, so I guess I am stuck with slow NDMP backups.
Just out of interest, does anybody understand why minra has an impact on backup speed. I assume the read ahead does not go past end of file but that is the only explanation I can think of as to why it would have an impact?
Regards, pdg
--
See mail headers for contact information.
On Thu, Aug 31, 2006 at 10:46:41PM -0700, Blake Golliher wrote:
Have you looked into Snapmirror to tape for your backups? You lose on incrementials, but that may not be a big deal for you. It's a block level backup of the entire volume. Might help speed things up.
Yes, I have. But I worry about doing a restore and losing a tape block. I suspect I might lose an entire volume that way.
Regards, pdg
--
See mail headers for contact information.
actually backing them up.
When you have a large volume it will take a while to look at each file, it's worse with volumes that have a large number of small files.
Good thought, but no.
The backup is slow after the metadata dump is finished.
Peak is slow as well (5 Meg or so).
Regards, pdg
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-
Blake Golliher -
Brian Pascal -
Carl Howell -
Eyal Traitel -
Peter D. Gray