Hi.

I'm experiencing a very strange problem since I installed OpenSolaris 2008.05 on a Sun Ultra 20 M2 workstation. Every now and then the system becomes incredibly slow and I strongly suspect that the guilty is an hard disk spin down.

The first time that the problem appeared I couldn't understand what happened because I logged out from the workstation, which remained powered on, and the following day logging in was a pain: the default desktop wallpaper loaded in 30 seconds or longer. Rebooting solved the problem. The problem continued to appear every now and then and one day, listening to music with the headphones, I heard the noise of the hard disk spinning down and the problem showed up again! That's why I suspect that for some reason the disk spins down and the system stops performing well. If a program is already loaded, it works perfectly, such as Firefox or Gnome itself, but as I try to access the file system, for example opening the file browser, Solaris is really really slow. Rebooting always solves the problem.

Have you got some suggestion to help me track down such problem?

Have you tried using iostat -En? If the disk is failing it should also start logging to /var/adm/messages.

Thank you keysorsoze.

I'll monitor the situation. I checked the log but found nothing. I'm beginning to suspect that the guilty is an external USB drive which is configured as a cache device in a zpool but I'm not sure about it. Yesterday the problem appeared again and before rebooting I was powering off the USB disks and as soon as I powered off this USB drive, the system started performing well again, but I don't know if it was a coincidence. Moreover, I imagine that a drive configured as a cache device in a zpool shoudln't affect so badly the system, even if mulfunctioning.

Assuming that nothing is logged, if I wanted to monitor the USB bus, what could I do? zpool iostat -v gave me no hints of something malfunctioning and the status of the zpool was good: every device appeared as online and there were no known data errors. By the way, I removed that drive from the zpool and let's see what happens.

Good morning Enrico,

To find out what exactly is happening behind the scenes, I suggest you try some DTrace scripts. You don't necessarily have to know the D language since there is a nice DTrace Toolkit available with lots of examples. This helped me a lot about learning DTrace and learning about what's happening in my Solaris system.
With respect to your prob there is "iosnoop" or "iopattern" or likewise scripts.
Just have a look at it at: http://www.brendangregg.com/dtrace.html

Hasta luego, C

Thank you very much coolster!

I'll look at it as soon as I go home and tell you about my progresses.

Hasta luego,
Enrico.