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Contribs.org Forums => General Discussion => Topic started by: purvis on March 20, 2015, 11:24:43 PM

Title: my FYI on reducing rebuilding raid 1 drives
Post by: purvis on March 20, 2015, 11:24:43 PM

I had wrote some back on this subject back in October 2013.
http://forums.contribs.org/index.php/topic,50272.0.html

I am using SME 8.1

Today I am rebuilding an raid 1 array with 2  drives that are 2 TB in size.
1 of the 2 TB drives was having issues due to drive errors found also using S.M.A.R.T. drive diagnostics.

After putting in a new 2 TB drive like the one before(I keep drives at my location on the shelf for this purpose).
And starting the new build. The time was going to take over 447 minutes.
After setting the NCQ to 1, that time dropped down to about 190 minutes.( finish=185.6min speed=160835K/sec).
The report previous speed was about 71000K/sec or something close to that before setting NCQ to 1

I have moved pretty much moved other servers to all SSD drives and the times to complete a rebuild is relatively small in time compared to this 2TB standard hard drive.

I will not be checking back on this post.
This post was just meant to save other people some time.

smartctl returned this info

Code: [Select]

# smartctl --scan
/dev/sda -d scsi # /dev/sda, SCSI device
/dev/sdb -d scsi # /dev/sdb, SCSI device

The code I was able to use for setting NCQ to 1 was

Code: [Select]

echo 1 > /sys/block/sda/device/queue_depth
echo 1 > /sys/block/sdb/device/queue_depth


I will do the usual update with the below instructions to let the NCQ reset back to the default(likely 32)  after the array rebuild process is complete
yum clean all
yum update -y
signal-event post-upgrade;signal-event reboot

Title: Re: my FYI on reducing rebuilding raid 1 drives
Post by: CharlieBrady on March 25, 2015, 06:55:17 PM

I assume you mean "reducing rebuilding time".

Title: Re: my FYI on reducing rebuilding raid 1 drives
Post by: TerryF on March 25, 2015, 11:30:51 PM

Interesting, are there any contrary implications?

Title: Re: my FYI on reducing rebuilding raid 1 drives
Post by: purvis on April 04, 2015, 04:12:12 AM

Reducing raid build time is right. I cannot edit the header to this post

Title: Re: my FYI on reducing rebuilding raid 1 drives
Post by: purvis on April 04, 2015, 04:18:34 AM

I will not be revisiting this post.
But I do think it would be good to NCQ on raid 1 rebuilds to a factor of 1.
I have not checked any behavior with the raid check routine.
I have kill that function on our systems with SSD. I run it once in a great while manually.