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Poor Performance on ES40 when using tar restore

Bill Zych
Occasional Visitor

Poor Performance on ES40 when using tar restore

We are running an ES40 with 12gb Ram and 3 866 CPUs. When doing a tar restore to disk the system gradually becomes unusable. It can take up to 15 minutes to get the Login prompt via telnet. This problem only happens when writing from tape to disk. When archive files to tape the system performs just fine.
4 REPLIES
Dave Bechtold
Respected Contributor

Re: Poor Performance on ES40 when using tar restore

Hi Bill,

- What version and patch level is installed on the system ?

I'm aware of an older problem under 4.0d-f that was fixed after PK2, where up to PK8 for v4.0f. You'd see allot of ss_perform_timeouts in the error log.

Maybe look at the binary.errlog to see if anything is being reported during the slowdown time. Maybe SCSI errors causing interrupts beating on the system. If you see "lid's do not match" errors on V5 you may need to cleanup rogue tape devices in the hardware database - I've seen that impact Legato performance.

- What's your tar command? what options used for the restore?

- Was the data in the tar archive written by this system? Or are you exchanging data from another platform/system?

- Watch the process with "ps" and see if it's consuming the system - %CPU, VSZ & RSS, and maybe use vmstat to see what modes the system is in during this time sys, user, int. You may need to renice your login process to watch these things.

Let us know.

Dave Bechtold

Alexey Borchev
Regular Advisor

Re: Poor Performance on ES40 when using tar restore

I've got something similar with vrestore.

During restore, (tape -> non-system disk), in a several minites, I start seeing traffic on system disk.

System disk havily loaded -> poor responce time.

Try to monitor it with iostat.
The fire follows shedule...
Ralf Puchner
Honored Contributor

Re: Poor Performance on ES40 when using tar restore

Or simple open a call within the support center. In such complex scenarios each detail counts and a generic answer can not meet your configuration/versions.

Help() { FirstReadManual(urgently); Go_to_it;; }
Dave Bechtold
Respected Contributor

Re: Poor Performance on ES40 when using tar restore

Hi Bill,

You may want to see if you can further isolate this by restoring a tar archive that is on another disk/filesystem to the target filesystem to see if it behaves similarly. To see if it's specific to reading the archive from the tape device.

Also, if the target file system is AdvFS, take a look at the fragementation of that domwin the file system sits on.

# defragment -nv {domain}

Then check the Aggregate I/O perf: - if it's 60% or below - consider deframenting the domain. If your on v5.1B check out vfast feature.

Dave Bechtold