Hi, I have a single BE server running all latest patches except 2014 SP1. I have two SAS based tape autoloaders connected to a dual port SAS card. One is LTO6 (Quantum) and the other is LTO5 (DELL). The LTO5 drive runs well. I recently needed a new drive and in our case a LTO6 autoloader was only a little bit more expensive than an LTO5 so I purchased this instead (Future proofing so that when the LTO5 dies we will buy another LTO6). However the LTO6 drive performance is worse than LTO5. I am measuring this by performing the same backup job to each tape drive (Literally one after the other - I am aware that variations occur due to the different times I am backing up - but this is a persistent pattern no matter when I test). Initially I attempted to use LTO5 tapes in the LTO6 unit (Because I do not want to be in a situation where the LTO6 drive fails and be unable to restore the data). I am aware that using the LTO5 tape in the LTO6 drive means I am limited to LTO5 throughput but I am not even getting that. After speaking to Quantum they suggested trying an LTO6 tape as a test. I have done this and performance is no better in BE. We than ran ITDT tools and the results show the drive is capable of pushing 160 mbps non-compressed and various higher numbers with compression, so it is not an issue with the unit. Things I have tried.... Tried amending various settings within BE (Such as block/buffer size etc..) Disconnecting the DELL unit (So the Quantum is only device connected to the SAS card) As mentioned LTO5 and LTO6 media Latest firmware/drivers on SAS card. server, autoloader, tape drives Devices show correctly in Device Manager (Autoloader - Unknown device, Tape drives using latest Symantec drivers via TapeInst.exe) I am backing up VMware VM's using AVVI and SAN Transport (With no GRT). I believe it is highly unlikely that shoe-shining etc. is occuring as throughput using LTO5 is around 8-13GB a min with a verify of 10-16GB a minute. I have opened several cases with Symantec about this and even though I explain the situation over and over again they are more obsessed with how I am doing the backup!!! Despite me telling them it does not matter what VM's I select etc. (And have sent job logs and the ITDT output to them). They even suggested backing up a different server (A physical one) to see if the problem is with AVVI. I have tried to tell them that my physical server jobs do not have the throughput to be able to see the problem but they do not understand and eventually I lose the will to live and give up with them! I can and have literally shown them BE performing the exact same backup job to each drive and the LTO6 always being considerably slower. Does anyone have any ideas?

What brand are the tape drives? What SAS card are you using? If it is a RAID card, please make sure it is supported. http://www.symantec.com/docs/TECH70907

How long did you spend tuning your LTO6 tape drive, i.e. changing block and buffer sizes?

Hi, They are DELL and Quantum. The SAS card is a DELL SAS 6GB External HBA (No RAID funtionality). Thanks

Hi, I spent quite a bit of time on this before contacting Symantec simply because generally I am aware performance tuning is very unique to each environment and it was faster for me to try things than get Symantec involved but I have reached a point where nothing seems to be making any difference?

Dell doesn't make tape drives. What brand did they resell you? What library/loader?

Forum Discussion

LozBC

Level 4

10 years ago

Backup Exec LTO6 slower than LTO5?? Symantec support not helping!

Hi,

I have a single BE server running all latest patches except 2014 SP1.

I have two SAS based tape autoloaders connected to a dual port SAS card.

One is LTO6 (Quantum) and the other is LTO5 (DELL).

The LTO5 drive runs well. I recently needed a new drive and in our case a LTO6 autoloader was only a little bit more expensive than an LTO5 so I purchased this instead (Future proofing so that when the LTO5 dies we will buy another LTO6).

However the LTO6 drive performance is worse than LTO5. I am measuring this by performing the same backup job to each tape drive (Literally one after the other - I am aware that variations occur due to the different times I am backing up - but this is a persistent pattern no matter when I test).

Initially I attempted to use LTO5 tapes in the LTO6 unit (Because I do not want to be in a situation where the LTO6 drive fails and be unable to restore the data).

I am aware that using the LTO5 tape in the LTO6 drive means I am limited to LTO5 throughput but I am not even getting that.

After speaking to Quantum they suggested trying an LTO6 tape as a test. I have done this and performance is no better in BE. We than ran ITDT tools and the results show the drive is capable of pushing 160 mbps non-compressed and various higher numbers with compression, so it is not an issue with the unit.

Things I have tried....

Tried amending various settings within BE (Such as block/buffer size etc..)
Disconnecting the DELL unit (So the Quantum is only device connected to the SAS card)
As mentioned LTO5 and LTO6 media
Latest firmware/drivers on SAS card. server, autoloader, tape drives
Devices show correctly in Device Manager (Autoloader - Unknown device, Tape drives using latest Symantec drivers via TapeInst.exe)

I am backing up VMware VM's using AVVI and SAN Transport (With no GRT). I believe it is highly unlikely that shoe-shining etc. is occuring as throughput using LTO5 is around 8-13GB a min with a verify of 10-16GB a minute.

I have opened several cases with Symantec about this and even though I explain the situation over and over again they are more obsessed with how I am doing the backup!!!

Despite me telling them it does not matter what VM's I select etc. (And have sent job logs and the ITDT output to them). They even suggested backing up a different server (A physical one) to see if the problem is with AVVI. I have tried to tell them that my physical server jobs do not have the throughput to be able to see the problem but they do not understand and eventually I lose the will to live and give up with them!

I can and have literally shown them BE performing the exact same backup job to each drive and the LTO6 always being considerably slower.

Does anyone have any ideas?

Windows Server (2003-2008)

12 Replies

Larry_Fine
Level 6
10 years ago
What brand are the tape drives?

What SAS card are you using? If it is a RAID card, please make sure it is supported. http://www.symantec.com/docs/TECH70907
pkh
Moderator
10 years ago
How long did you spend tuning your LTO6 tape drive, i.e. changing block and buffer sizes?
LozBC
Level 4
10 years ago
Hi,

They are DELL and Quantum.

The SAS card is a DELL SAS 6GB External HBA (No RAID funtionality).

Thanks
LozBC
Level 4
10 years ago
Hi,

I spent quite a bit of time on this before contacting Symantec simply because generally I am aware performance tuning is very unique to each environment and it was faster for me to try things than get Symantec involved but I have reached a point where nothing seems to be making any difference?
Larry_Fine
Level 6
10 years ago
Dell doesn't make tape drives. What brand did they resell you?

What library/loader?
pkh
Moderator
10 years ago
Check your tape statistics. See whether there are a lot of soft and hard errors. If there are, you need to change your tapes and/or your tape drive. See my article below https://www-secure.symantec.com/connect/articles/tape-statistics-explained
dfeifer
Level 4
10 years ago
Log in to the on board remote management of the quantum drive and watch the Drive Status. Willing to be the drive is going idle quite a bit because data is not being pushed to it fast enough.
DaranDazza
Level 4
10 years ago
I am also having the same problem with every LTO6 Tape drive - We operate out of a centralised Support Help Desk and we service 1300 locations (remotely) - 2 or more servers per site.... running BE2010 R3 on Win2008 R2 servers.

These sites are upgrading from LTO5 to LTO6 and we are now seeing extensive time lengthening - from LTO5 taking a maximum of 6 hours (backup and verify - depending on the data in each location) to having LTO6 taking an average of 14 hours - (backup and verify) - in some cases it has extended to 18 hours and in another (just notified) - taking 24 hours to backup and verify.

We have tried the latest IBM driver for the LTO6 and also applied tapeinst.exe which installs the 2008 symantec driver - all to nil avail.

We also desperately need help - (the only way to cut down the time is to remove the VERIFY option - which we don't like to do but desperate measures are required).
DaranDazza
Level 4
10 years ago
We have found that the LTO6 cards were installed in a slow slot on the Motherboard - changing over to a faster slot has increased the speed of the backup lessening time taken.
CalintzChang
Level 1
10 years ago
I am having the same issue as well.

We added an Fujitsu Eternus LT260 tape library with HP FC LTO6 drives. The backup writing job rate from Backup Exec was between 1 - 3 MB/min. This is drastically slow.

While I have also LTO5 drives attached via SAS connection, my VM backup via SAN transport gave me 3000MB/sec throughput.

Is this issue gotta do with hardware or Backup Exec 2014 software?

Kindly advise if you manage to solve this issue.