Why are there reads on my backup HDD?

[IceBoosteR]

Hi all,

I have attached one external USB drive (8TB) for daily backup. I have written a backup script, wehcih is running as a daily cronjob once at night. But I do see activity on that particular HDD every one to three hours, with some small reads (under 100k). This is causing the disk to spin up very often - and I do want to understand why this happens. I mean, I do not do anything on that drive, so a system process is causign this.
How can I find out more and suppress this behaviour?

Thanks,
Ice

 

[DrKK]

Most people don't even bother trying to "spin down" their disks on FreeNAS. It's just almost impossible these days. It's probably some management script.

I usually give people a hard time for trying to spin down drives, but in Germany, where electricity is actually four times what I pay for it, using even a couple watts less is relevant. Good luck sir, let's see if anyone has a better answer.

 

[IceBoosteR]

Most people don't even bother trying to "spin down" their disks on FreeNAS. It's just almost impossible these days. It's probably some management script.

I usually give people a hard time for trying to spin down drives, but in Germany, where electricity is actually four times what I pay for it, using even a couple watts less is relevant. Good luck sir, let's see if anyone has a better answer.

Hi DrKK,
for my other 10 hard drives, I have the spindown disabled of course. Yes the electricity costs hurts sometimes, but it does not makes sense to spin down the NAS drives. I am only wondering why the external drive (its a Seagate one, and yes, this puppy needs around 8 watts) is accessed.
Maybe you're right and it's a management script, but what is it checking? "Yeah the disk is not dead, yeah" - or whatever it does :P

-Ice

 

[Stux]

Are you running any scripts which check drive temperatures or anything like that?

 

[IceBoosteR]

Are you running any scripts which check drive temperatures or anything like that?

Nope. No custom script which is reading anything from that drive.
And no script at all :D

 

[MrToddsFriends]

Just to be sure: Are there any shares configured on the backup pool? Snapshots?

According to the reporting graphs I'm seeing no I/O activity on my backup pool at all (with constantly spinning disks, fed by ZFS replication) besides the obvious ones (replications, scrubs).

 

[IceBoosteR]

No, no share on that drive.

I will have a look again today if there is maybe a change in the reporting graphs....

 

[IceBoosteR]

I double checked this. There are times where there is zero activity on the pool, as it should be. But then there are tims, where load is on the pool, but without anything actively started by myself. But I do see that during those times, there is also load on the other pool. But I do not see why this is happening.
I have checked with lsof if I see anything, but it seems to be luck to get whats happening there. I mean this are KB/s and not even many.

 

[IceBoosteR]

Hi,
I have observed the disk/pool the last days. When there is absolutely zero activity on my system, the backup drive is not touched in any way. No reads or writes. But when there is activity on my main pool, also on the backup pool is the msall activity I have written about.