Defrag and Scrub

Question

Is it necessary to run a scheduled scan on my RN314 for Defrag and Scrub?Volumes are only JBOD and no Snapshots.If so how often should these be scheduled to run?&nbsp;

StephenB · Answer

claynz&nbsp;wrote:
Is it necessary to run a scheduled scan on my RN314 for Defrag and Scrub?
Volumes are only JBOD and no Snapshots.
If so how often should these be scheduled to run?&nbsp;

Scrub does both a btrfs scrub and a RAID scrub.&nbsp; While the RAID scrub doesn't apply to JBOD, the btrfs scrub does.&nbsp;&nbsp;
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None of these are strictly "necessary".&nbsp; While the defrag is the least useful, I do run it.
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My own practice (on all my NAS) is to run one maintenance task a month on each volume.&nbsp; On NAS with multiple volumes, I stagger the schedule so only one task is running at a time.
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claynz · Answer

I've noticed the Shares are set to auto-defrag, is this different to volume defrag? should I also enable Bit Rot Protection?

Would this work ok

Defrag every month on the 1st

Scrub every month on the 20th

So can all volumes be defrag or scrub at once?

StephenB · Answer

claynz&nbsp;wrote:
&nbsp;
Would this work ok
Defrag every month on the 1st
Scrub every month on the 20th
&nbsp;

Up to you, personally I space them out (and run them every four months, since I only run one of the tests each month).
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Don't neglect balance and the disk test.&nbsp; IMO they are the most valuable.&nbsp;
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claynz&nbsp;wrote:
I've noticed the Shares are set to auto-defrag, is this different to volume defrag?

It's the same defrag process, just run for the share instead of the entire volume.&nbsp; I don't know what triggers auto-defrag to run.
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claynz&nbsp;wrote:
should I also enable Bit Rot Protection?
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Personally I enable it.&nbsp; It enables BTRFS checksums on the share, which would give you some more information on what files are damaged if the disk starts to fail.&nbsp;
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schumaku · Answer

How comes the Bit Rot Protection isn't enabled on this volume?

Sandshark · Answer

Bit rot protection does slow things down a bit, and I don't believe it's the default.&nbsp; So it's off because you didn't turn it on.&nbsp; &nbsp;Note that turning it on at this point may not have the effect you want, as it will only affect files created after you enabled it.&nbsp;The various maintenance tasks cannot overlap, at least if you use the GUI to run them.&nbsp; There would be a lot of disk thrashing, and I think doing a defrag (moving sectors of data) would cause issues with a scrub or balance.&nbsp; Note that if a scheduled task comes up while another is ongoing, it appears it's cancelled, not deferred, so make sure you allocate sufficient time between them.&nbsp; That's one reason for the one task a month plan.&nbsp; In my case, I have three NAS and schedule the tasks on different weeks, allocating two weeks for the scrub since it can sometimes take long.&nbsp; That keeps the added heat and noise down to just one NAS at a time.

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Defrag and Scrub

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