leave drive spun down


tomo

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5 hours ago, itimpi said:

I very much doubt this is possible.    I think you will find that the drives need to be spinning to allow them to be cleanly unmounted.

 

Quite right.

 

Unmounting the file system does indeed require a write to the disk. And part of unmounting is flushing any write buffers to the disk. The disk has to be spinning to do these activities.

 

It is possible that by spinning up the drives serially before the stop array request is made, the intensity of the power spike could be reduced. (When a drive is spinning up it will pull more power than keeping one spinning.) You could do the spinups manually or with a simple script. But it could also be that the way the array stop works, the disks are spun up serially anyway. Not 100% sure.

 

What is the concern? Power usage? Or stress on the PSU? I don't think either should be of much concern.

 

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2 hours ago, SSD said:

 

What is the concern? Power usage? Or stress on the PSU? I don't think either should be of much concern.

 

 

If you have 24 drive all spinning up in an uncontrolled manner, this would be a concern for the PSU which would see a massive spike. When the tower is first turned on, the SAS cards are intelligent enough to spin one up at time

 

if unraid would be clever enough to spin up one drive at a time and then unmount it, that would be better for the health of a PSU long term.

 

According to my power meter, peak usage was 740w

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5 hours ago, tomo said:

if unraid would be clever enough to spin up one drive at a time and then unmount it, that would be better for the health of a PSU long term.

Far more to this request that simply at shutdown / stopping the array.

 

Because unRaid can spin up any/all drives concurrently under various circumstances (parity check starting, drive became disabled, or even simply simultaneous reads/writes from all drives etc) I would think that this would be a rather big overhaul to how the system handles things.

 

5 hours ago, tomo said:

When the tower is first turned on, the SAS cards are intelligent enough to spin one up at time

 

True enough.  But, the assumption that HBA's tend to make is that drives are in one or more RAID groups and that the drives themselves stay spinning once spun up.

Edited by Squid
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