Very slow verify

[jdpal]

Hi,

 

I am running Retro 7.6 on W2k3. I recently expanded the C: partition from 12GB to 50GB as I heard it would help media verify operation. It appears that my disk sets do indeed do media verifies faster.

 

However, I have a tape set that crawls on verify no matter if it's media verification or thorough verification.

 

Here is the log from the latest job, which I cancelled after 2 days...

 

 

+ Recycle backup using Servers at 11/21/2008 8:00 PM (Execution unit 2)

To Backup Set Servers B...

11/21/2008 8:00:01 PM: Recycle backup: The Backup Set was reset

 

- 11/21/2008 8:00:01 PM: Copying Accounting on CLEESE

11/21/2008 8:06:21 PM: Snapshot stored, 91 KB

11/21/2008 8:06:22 PM: Comparing Accounting on CLEESE

11/21/2008 8:40:58 PM: Execution completed successfully

Completed: 149 files, 538.7 MB

Performance: 30.4 MB/minute (371.4 copy, 15.8 compare)

Duration: 00:40:57 (00:05:33 idle/loading/preparing)

 

 

- 11/21/2008 8:41:01 PM: Copying Repositories on Dev Server

11/21/2008 8:45:23 PM: Snapshot stored, 2,085 KB

11/21/2008 8:45:28 PM: Comparing Repositories on Dev Server

11/21/2008 11:56:53 PM: Execution completed successfully

Completed: 8854 files, 4.0 GB

Performance: 42.0 MB/minute (1054.5 copy, 21.4 compare)

Duration: 03:15:52 (00:01:59 idle/loading/preparing)

 

 

- 11/21/2008 11:56:54 PM: Copying ebooksearch on FERRELL

11/21/2008 11:57:44 PM: Snapshot stored, 17 KB

11/21/2008 11:57:46 PM: Comparing ebooksearch on FERRELL

11/21/2008 11:58:27 PM: Execution completed successfully

Completed: 21 files, 755 KB

Performance: 9.8 MB/minute (6.3 copy, 44.2 compare)

Duration: 00:01:33 (00:01:24 idle/loading/preparing)

 

 

- 11/21/2008 11:58:29 PM: Copying vPage on FERRELL

11/22/2008 12:07:34 AM: Snapshot stored, 20.9 MB

11/22/2008 12:07:54 AM: Comparing vPage on FERRELL

11/22/2008 2:03:39 AM: Execution completed successfully

Completed: 138274 files, 2.9 GB

Performance: 47.9 MB/minute (392.1 copy, 25.5 compare)

Duration: 02:05:09 (00:03:03 idle/loading/preparing)

 

 

- 11/22/2008 2:03:41 AM: Copying Tomcat 6.0 on MAHER

11/22/2008 2:04:38 AM: Snapshot stored, 86 KB

11/22/2008 2:04:39 AM: Comparing Tomcat 6.0 on MAHER

11/22/2008 2:04:56 AM: Execution completed successfully

Completed: 246 files, 47.7 MB

Performance: 439.5 MB/minute (357.0 copy, 714.1 compare)

Duration: 00:01:15 (00:01:01 idle/loading/preparing)

 

 

- 11/22/2008 2:04:59 AM: Copying Tomcat 6.0 on lewis

11/22/2008 2:10:49 AM: Snapshot stored, 95 KB

11/22/2008 2:10:51 AM: Comparing Tomcat 6.0 on lewis

11/22/2008 2:55:11 AM: Execution completed successfully

Completed: 309 files, 4.2 GB

Performance: 183.8 MB/minute (867.0 copy, 102.8 compare)

Duration: 00:50:12 (00:03:50 idle/loading/preparing)

 

 

- 11/22/2008 2:55:13 AM: Copying syncdata on lewis

11/22/2008 6:43:45 AM: Snapshot stored, 52.4 MB

11/22/2008 6:44:34 AM: Comparing syncdata on lewis

11/24/2008 9:28:33 AM: Execution stopped by operator

Remaining: 141244 files, 152.9 GB

Completed: 71156 files, 124.4 GB

Performance: 126.2 MB/minute (1280.7 copy, 41.9 compare)

Duration: 2 06:33:21 (00:15:59 idle/loading/preparing)

 

11/24/2008 9:29:09 AM: Execution stopped by operator

Total performance: 118.9 MB/minute

Total duration: 2 13:28:33 (00:32:51 idle/loading/preparing)

 

 

Any suggestions for what to look at to increase the verify speeds? This is on thorough verification but the results have been similar with media verify.

 

Thanks!

[Mayoff]

Slow tape reads could be caused by dirty tape heads or even a device communication problem.

 

You can try different device cables after cleaning the tape heads.

 

what type of tape drive is this? How is it connected?

[jdpal]

Hi Mayoff,

 

I ran a cleaning tape through the drive twice. The drive did need to be cleaned (and apparently there was not a cleaning tape in the autoloader for quite some time).

 

It is a Sony AIT-4 DC drive in a Qualstar robotic library, attached via SCSI.

 

I performed the following tests:

 

I took a brand new tape and created a new tape set for it, adding it as the only member. I then backed up a 10GB folder full of MP3 files. The backup averaged 1266MB/Min. I had it set to media verify. The media verify chugged along at about 65MB/Min before I canceled it.

 

Then I did a restore from that new tape to a hard drive array directly attached to the retrospect server. The restore also chugged along at about 65MB/Min.

 

I did not switch SCSI cables simply because the writing is fine but the reading isn't. What do you suggest? Is there a way in Retrospect to get more information about the slowdown?

 

Thanks!

[Mayoff]

The drive could have a problem with the read heads. It may be worth contacting Sony about this problem. I have seen it before, and drive failure is a possibility.

 

 

[jdpal]

Hi Mayoff,

 

We did a firmware upgrade which solved the performance problem with reads. Thanks!