I've recently set up an unRAID system, basically uneventful thanks to all the excellent info available here. But this entry in my syslog is bugging me because I don't know why it shows up, kinda randomly. FYI, /dev/sde is my cache drive.

 

Mar 25 05:01:07 Tower emhttp: shcmd (54): /usr/sbin/hdparm -y /dev/sde >/dev/null (Drive related)

 

Can somebody tell me what this is?

 

Thanks... - Mike

 

I believe is is spinning down the cache drive, or trying to at least.

I believe is is spinning down the cache drive, or trying to at least.

 

Checking out hdparm online, I found this:

 

-y

    Force an IDE drive to immediately enter the low power consumption standby mode, usually causing it to spin down. The current power mode status can be checked using the -C flag.

 

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The drive in question is not an IDE drive, it's a SATA:

 

/dev/sde1 WDC_WD10EACS-00D6B0_WD-WCAU40410745

 

Here's another blurb from the syslog:

 

Mar 24 04:13:17 Tower kernel: mdcmd (56): spindown 0 (Routine)

Mar 24 04:13:18 Tower kernel: mdcmd (57): spindown 1 (Routine)

Mar 24 04:13:18 Tower kernel: mdcmd (58): spindown 2 (Routine)

Mar 24 04:13:19 Tower kernel: mdcmd (59): spindown 3 (Routine)

Mar 24 04:13:19 Tower kernel: mdcmd (60): spindown 4 (Routine)

Mar 24 04:13:19 Tower emhttp: shcmd (44): /usr/sbin/hdparm -y /dev/sde >/dev/null (Drive related)

 

I'm assuming here that '0' is the parity drive and '1' - '4' are data drives. If that means the cache drive is '5', I've never seen a syslog entry with a 'spindown 5'.

 

In the interest of total disclosure the drives are arranged as follows:

 

/dev/sda - parity

/dev/sdb - data

/dev/sdc - data

/dev/sdd - data

/dev/sde - cache

/dev/sdf - data

 

I wasn't sure if the last data drive could be added after the cache drive, but since I hadn't read anything about the order of adding drives, I put it at the end with the plan to pull the cache drive and move the data drive up one notch, then add the cache drive back in... but that hasn't happened yet. Perhaps this arrangement is leading to the syslog entries I'm seeing?

Perhaps this arrangement is leading to the syslog entries I'm seeing?

The order of the drives does not matter and would not effect what you are seeing.

 

The reason you see the spindown 0, spindown 1, ect is because that is what is being shown to you by the unRAID control code for spinning down the drives.  It is down this way because of the group spinup and group spindown logic.  The cache drive IS NOT part of the array and therefore does not belong to a spinup group and there spindown group.  The hdparm -y command spins down the drive and unRAID is showing you that.

 

It is nothing to worry about and is normal when you have a cache drive in the system.  I had these in my logs when I was allowing my cache drive to spin down... my cache drive is now active at all times, so it never gets a chance to spin down.

Perhaps this arrangement is leading to the syslog entries I'm seeing?

The order of the drives does not matter and would not effect what you are seeing.

 

The reason you see the spindown 0, spindown 1, ect is because that is what is being shown to you by the unRAID control code for spinning down the drives.  It is down this way because of the group spinup and group spindown logic.  The cache drive IS NOT part of the array and therefore does not belong to a spinup group and there spindown group.  The hdparm -y command spins down the drive and unRAID is showing you that.

 

It is nothing to worry about and is normal when you have a cache drive in the system.  I had these in my logs when I was allowing my cache drive to spin down... my cache drive is now active at all times, so it never gets a chance to spin down.

 

Great... thanks for putting my mind at ease.

 

Just curious, other than the initial write to the cache drive, what's the advantage of the cache drive staying active? And, what determines whether the cache drive spins down or not?

Drives spindown after a configurable period of inactivity. They spinup when accessed.

There really is no advantage to it staying active... it just happens that way for me as I have torrents being servered from that drive.  The torrents keep the drive running all the time anyway... so I just set spindown on the drive to never as a little extra insurance so to speak.