But, isn't the goal to test whether changing the minra setting effects the backup of the volume in question? I'm not suggesting breaking the mirror every time he needs to run a backup. If changing the minra setting is effective, then an RFE is certainly warranted. If not, he has some other problem. Wouldn't you agree?
- Carl
-----Original Message----- From: Blake Golliher [mailto:thelastman@gmail.com] Sent: Friday, September 01, 2006 10:57 AM To: Carl Howell Cc: Brian Pascal; toasters@mathworks.com Subject: Re: when to use minra ?
I think the problem there is that you are breaking the snapmirror. I think we want to avoid that.
-Blake
On 9/1/06, Carl Howell chowell@uwf.edu wrote:
Vol options cannot change in snapmirror destinations?
I'm running 7.0.4 on our R200 and I can do this with no problems.
- snapmirror break destvol
- vol options destvol minra on
Am I missing something?
- Carl
-----Original Message----- From: owner-toasters@mathworks.com
[mailto:owner-toasters@mathworks.com]
On Behalf Of Brian Pascal Sent: Friday, September 01, 2006 12:03 AM To: Peter D. Gray Cc: owner-toasters@mathworks.com; toasters@mathworks.com Subject: RE: when to use minra ?
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 AMWhy 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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