HP LTO6 tape issues

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Re: HP LTO6 tape issues

Veeam Logoby lightsout » Mon Mar 09, 2015 5:42 pm 1 person likes this post

Can I suggest looking at this thread, for my fun with a LTO-6 library.

http://forums.veeam.com/tape-f29/spectralogic-t50e-how-to-get-it-working-t18924.html

Specifically this bit:

•At HKLM\Software\Wow6432Node\Veeam\Backup and Replication, create DWORD value SkipTapeAlerts = 1
•Extend the polling interval at HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Veeam\Veeam Backup and Replication\TapeDeviceWatcherTimeoutSec
•DWORD – polling interval in seconds (set to decimal 300 = five minutes)


Since then, it has been working fine. Like you though, my jobs would fail randomly whilst running.
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Re: HP LTO6 tape issues

Veeam Logoby 20100 » Tue Mar 10, 2015 2:41 am

Hi

I just tried Lightsout changes and unfortunately it still failed.
Then I tried Velimira changes and it failed as well.
When it does, I still can see the following error in Windows Event Viewer: The device, \Device\Tape0, is not ready for access yet.

I should have a new tape controller tomorrow for me to try. Unfortunately it was not possible to add it directly on the second bank (needs a second CPU apparently), so will have to remove a 10Gb NIC to make room for it

I will let you know how it goes.

Once again, thanks for all the contributors. It is great to see such a caring community.
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Re: HP LTO6 tape issues

Veeam Logoby lightsout » Tue Mar 10, 2015 1:56 pm

Only other point I'd add is I found it to better with the built-in Windows drivers, then the IBM LTO drivers. Along with the registry changes I made!
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Re: HP LTO6 tape issues

Veeam Logoby EdZ » Tue Mar 10, 2015 4:09 pm 1 person likes this post

To update my post from yesterday.

Removing the HP WBEM version 10 has resolved my issue.
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Re: HP LTO6 tape issues

Veeam Logoby 20100 » Wed Mar 11, 2015 12:45 am

Well, last night, as I removed our 10Gb Nic card to leave space for an extra tape controller, I rebooted the server and miracle, this morning I found that the tape copy worked for the first time!

I performed another tape copy from the other job that failed last week-end and it worked too!

I do not know what the fix was, either the HP WBEM either the registry change, but it looks like a reboot was necessary to activate it properly.

I am so grateful with this community to have solve this issue with its help. Thanks all.

If I may hijack this thread a little more: for those that use LTO6, what sort of processing rate do you get?
I was expecting more compared with our LTO5 using HP Dataprotector. However I noticed that HP DP uses more agents to read the disks, so more data are written to tape at the same time. Here that might might the bottleneck as there is only 1 file to write and the tape must be waiting for more data.
Saying that Veeam thinks the bottleneck is the target (tape drive) at 99%, so not too sure.

Thanks
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Wed Mar 11, 2015 2:54 am

Hi,

I've got an HP MSL2024 Tape Library connected via 8gb Fibre and I get 'Processing Rate' anywhere from between 150 MB/s to 80 MB/s..

Not too sure why its so inconsistent !! Seems like in the middle of the job, the 'throughput' remains almost 0 for many minutes before intermittently kicking in again !

Image

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Re: HP LTO6 tape issues

Veeam Logoby tsightler » Wed Mar 11, 2015 3:01 am

20100 wrote:If I may hijack this thread a little more: for those that use LTO6, what sort of processing rate do you get?
I was expecting more compared with our LTO5 using HP Dataprotector. However I noticed that HP DP uses more agents to read the disks, so more data are written to tape at the same time. Here that might might the bottleneck as there is only 1 file to write and the tape must be waiting for more data.
Saying that Veeam thinks the bottleneck is the target (tape drive) at 99%, so not too sure.

Since Veeam data is already compressed and there is just a single big file it should be pretty easy for a single agent to stream at the full tape speed, which for LTO-6 is around 160MB/s. I would expect real world speeds in the 130-160MB/s range assuming everything else is optimal. Some people are used to seeing speeds of 300MB/s in other software, but that's writing data that is not already compressed. Since an LTO-6 tape device can do 2.5:1 compression in hardware it is capable of receiving uncompressed data at around 400MB/s (160MB/s x 2.5 compression = 400MB/s), but Veeam backups are generally already compressed at similar levels and thus you'll be much closer to the actual native speed instead.
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Wed Mar 11, 2015 3:09 am

but Veeam backups are generally already compressed at similar levels and thus you'll be much closer to the actual native speed instead.


then why is it so intermittent in my case ? Why does the backup get paused intermittently while transferring data to tape ?
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Wed Mar 11, 2015 9:26 am

I'm doing a backup as i type this and again.. the throughput has dropped to 0kb for the last half hour !!

Can someone please shed some light on this ? What logs do i check to see whats going on ?

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Re: HP LTO6 tape issues

Veeam Logoby tsightler » Wed Mar 11, 2015 11:51 am

jazzoberoi wrote:I'm doing a backup as i type this and again.. the throughput has dropped to 0kb for the last half hour !!

Can someone please shed some light on this ? What logs do i check to see whats going on ?


I don't know that this is the type of problem that can be resolved via the forum as it's pretty difficult to understand what's going on. Are there other backups running during this time as well, or just the backup to tape? I certainly wouldn't expect that behavior if there's nothing else going on.
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Re: HP LTO6 tape issues

Veeam Logoby 20100 » Wed Mar 11, 2015 8:27 pm

Hi Tom

Thanks for reply. Yes this is the type of speed I am getting, so it looks we are OK.
Obviously our previous backup solution does backup non compressed data which explain the speed difference.
It has also been confirmed with the amount of data on tape, which you already explained to me in a different thread.

Thanks again
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Wed Mar 11, 2015 9:14 pm

tsightler wrote:I don't know that this is the type of problem that can be resolved via the forum as it's pretty difficult to understand what's going on. Are there other backups running during this time as well, or just the backup to tape? I certainly wouldn't expect that behavior if there's nothing else going on.


No other backup is running. Checked the Task Manager and everything is normal, CPU is below 20% and plenty of RAM available..
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Thu Mar 12, 2015 9:51 am

Hi, opened up a case # 00829368. Lets see what comes out of it !
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Re: HP LTO6 tape issues

Veeam Logoby tsightler » Fri Mar 13, 2015 1:53 am

jazzoberoi wrote:Hi, opened up a case # 00829368. Lets see what comes out of it !


I will follow the case as well as I'm definitely interested in what is causing this, it's certainly not something I would expect. In the vendor testing that I've done we've generally seen quite consistent performance for large files. The only time I ever see anything like what your posting is when backing up directories that have lots of smaller files but that doesn't seem to be the case in your screenshot. It will be very interesting to see what support has to say.
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Re: HP LTO6 tape issues

Veeam Logoby jazzoberoi » Sun Mar 15, 2015 11:38 pm

Hi Tsightler,

Could you please get someone to provide an update to the case ? I've already uploaded the logs as requested.
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