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Slow read with Ultrium 1840E Drive and Imation tapes

Thomas Braun
Advisor

Slow read with Ultrium 1840E Drive and Imation tapes

Hi,

I'm experiencing very slow reads with Imation tapes on the drive mentioned in the subject.

I tested with StorageWorks LTT and got the following results:

4.0 GB written in 75.9 seconds at 52.7 MB/s (Min 49.8 MB/s, Max 57.7 MB/s)

4.0 GB read in 540 seconds at 7.4 MB/s (Min 0.8 MB/s, Max 103.8 MB/s)

When watching the read progress it seems as if it starts very fast and gets slower and slower while reading the data.

I also updated to the latest firmware B5AD - but this also does not help.

Any idea what could cause this?
10 REPLIES
Johan Guldmyr
Honored Contributor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Hey, what is this 1840E connected to? (what kind of controller, cable etc)

Is it faster with other tapes - like HP tapes?
Has it been fast before?
What about the source (where you keep the data on) - can that handle the speed of the 1840E?

What about the other resources on the server, can you monitor them at the time you run the test? Are any of them exhausted (memory, cpu etc)?
Marino Meloni_1
Honored Contributor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

A suppport ticket collected immediately after the test, can help to understand the cause of the issue.
Is this occuring only with that batch of tape?
does it occurs also with HP tapes?

how is the drive connected to the host? scsi, sas, FC?

I would suggest to run the test again and immediately after, collect a support ticket, and attach it here, it may give us some hints on the cause of the issue
Thomas Braun
Advisor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Hi,

thanks for the feedback - see attachement for the support ticket information.

Just a few information before that:

HP tapes are performing as expected, but I think the overall throughput could be better, the following is a test with an HP tape with 64 GB data - first 2:1 Compression data and then Random:

Device Performance Test Started on Drive (Ultrium 4-SCSI) (Tape0)
Testing with 2:1 Compression Ratio
64.0 GB written in 1279 seconds at 50.1 MB/s (Min 0.1 MB/s, Max 105.3 MB/s)
64.0 GB read in 1099 seconds at 58.2 MB/s (Min -111848.1 MB/s, Max 88.6 MB/s)
Testing with Random
64.0 GB written in 847 seconds at 75.6 MB/s (Min 9.6 MB/s, Max 103.6 MB/s)
64.0 GB read in 726 seconds at 88.2 MB/s (Min 19.0 MB/s, Max 109.7 MB/s)

Thomas
Marino Meloni_1
Honored Contributor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

I had a review of the "ticket" you attached here, (this is only a small part of the ticket in html format, the complete one in native format would have more interesting info.
What I can see is that the last test (not sure if it is related to imation tapes or HP tapes) show that you may have some read/write issues.
in the "drive History > Event Log > Power-On Count:13"
we see that:
several Brush clean during write process (that mean the ReadAfterWrite process detect that data where not recoreded correctly)
Several Read Retry during read process

those are indicating you have issue with the tape or the R/W head

How to proceed:

You need to clean your drive with a non expired Cleaning Tape, may be a couple of time in a row
then use a brand new tape and run some tests, and see if the problem is still there

A read write problem may cause a slow down in performances due to retry and algorithm used to recover the errors.

Thomas Braun
Advisor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Well - all HP tapes that I tested are used... I currently have no *new* HP tapes.

The Imation tapes are *brand new*

I think I have had the slow read issue once or twice even with the HP tapes - the backup was fast, but the verify slowed down to a crawl and I had to interrupt it otherwise it would have last 48 hours.

Normally the backups including verify take around 10:30 hours for nearly 800 GB data.

I will run a cleaning tape and test again and attach the native report this time.
Thomas Braun
Advisor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Hi,

it's me again

Unfortunately, I now even can't use LTT anymore.

As soon as LTT tries to access the drive the server crashes with a blue screen...

HELP! :-(
Johan Guldmyr
Honored Contributor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

is the backup software/service disabled?
Thomas Braun
Advisor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Backup software (BackupExec) is shut down.

This problem started today when I installed version 4.11 of tape tools... removing and re-installing 4.10 does not help.

I just checked - bakcup ist working, it is just LTT scanning for devices that causes the problem.

Most likely related to the mraid35x.sys driver... see http://h30499.www3.hp.com/t5/Tape-Libraries-and-Drives/Tape-tools-reboots-server/m-p/4663655#M25937

LTT Team
Valued Contributor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

Hi,

This issue (crash) may happen if you have myraid drivers installed on the system.

Please send us the eventlogs and support ticket to ltt.team@hp.com
we will look into it.

L&TT Support
Thomas Braun
Advisor

Re: Slow read with Ultrium 1840E Drive and Imation tapes

There is a mxraid driver present, but this driver was on this system from the beginning and I have used LTT several times on this server without any problems.

I will create a support ticket and send it to the email address you mentioned.