immense delayed write to file system (ZFS and UFS2), performance issues

[Chuck Swiger]

Hi--

On Jan 26, 2010, at 10:45 AM, Dan Naumov wrote:
>  9 Power_On_Hours          0x0032   100   100   000    Old_age
> Always       -       136
> 193 Load_Cycle_Count        0x0032   199   199   000    Old_age
> Always       -       5908
> 
> The disks are of exact same model and look to be same firmware. Should
> I be worried that the newer disk has, in 136 hours reached a higher
> Load Cycle count twice as big as on the disk thats 5253 hours old?

Yes.  Drive actuators are (or used to be) typically rated for at least 50,000 load-cycle counts; at ~1000 events per day, there's about a 50% chance of such a drive dying before two years are up:

  http://en.wikipedia.org/wiki/Hard_disk_drive#Landing_zones_and_load.2Funload_technology

Some models of drives intended for laptops (typically smaller 2.5" form factor w/ single platter) can tolerate many more load-cycles, and newer drives also claim to handle more.

Regards,
-- 
-Chuck