#Volume option atime-update on SAN volumes

1 messages · Page 1 of 1 (latest)

mystic olive
kind oracle
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it helps reduce metadata invalidation. It's not a big deal these days on SSD drives, but it was important in some SATA scenarios. To be fair I have never seen a measurable performance impact either way, but on the other hand there's almost zero applications that actually do care about ATIME so it never hurts to just disable it.

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they added the atime-update-period parameter so that you can still have somewhat reliable atime updates without the metadata impact, by having WAFL update the atime on-disk only after X seconds. Less granularity, of course, but again no recent application that I know of actively relies on atime

mystic olive
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Thank you for the input.
It's kind of annoying that you have to be in advanced mode to set the atime-update option, know of any way of setting it at creation of volume?

kind oracle
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no, but as I explained, you can usually leave it on as it doesn't have any negative impacts on performance these days. the atime-update-period can be set during volume creation, but also only in advanced mode

vivid dawn
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If you are creating the volumes from the CLI, you can run both commands (vol create / vol mod) on one line:

set adv -c off;vol create -vserver <svm> -volume <vol> -aggregate <aggr> -size 4.1t;vol mod -vserver <svm> -volume <vol> -atime-update false;set adm -c on

We disable atime updates on all SAN volumes as part of our standard deploy. We leave it enabled on NAS volumes.

mystic olive
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Ok, thank you!

gray cove
rocky igloo
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@gray cove I have not seen the one you noted. It certainly lists more details but things like the tcpipheapsize are different compared to the older versions of Otv

gray cove
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Those are for the esxi. I believe the volume settings are still valid