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Throughput Tweaking

Created: 29 Apr 2013 | 3 comments

We just recently purchased a new quantum superloader 3 lto5 tape library. After setting up the new drive I did a test backup of the backup server itself to include the b2d storage raid 1,091 GB total and it accomplished the job at a rate of 11,883.02 MB/min. This had me pretty stoked because the previous drive was lucky to pass 2.1 MB/min. 

Where I see an issue though is with backing up other servers on the network. Those are completing with a job rate between 2,300-2,800 MB/min physical, 1,600-2,000 MB/min virtual and verifies are running between 17,000-24,000 MB/min.

Is this as expected? Or is this a sign of something wrong on the network side? We have an equallogic san that our vms reside on with its own gigabit network. Copying a directory on our file/print server from one iscsi location to another on the same san gives me a transfer rate of 22 MB/sec which seems awefully slow to me. (2.3 gig directory)

 

Operating Systems:

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teiva-boy's picture

You need to install SANHQ on your environment, and benchmark your SAN.  It's free software that came with your equallogic arrays from Dell.  It can tell you your IOPS, MB/s as well as peak loads.  

This is about normal IMO, tape is NEVER the bottleneck with modern technology.  It's usually something else like the clients, networker, file type, filesystem, SAN, etc...  LTO4 can write at up to 120MB/s natively, 180MB/s with compression.  thats 7200MB/min in BackupExec speak.  Again, never a tape issue most days.

There is an online portal, save yourself the long hold times. Create ticket online, then call in with ticket # in hand :-) http://mysupport.symantec.com "We backup data to restore, we don't backup data just to back it up."

pkh's picture

1) Make sure that in the Windows Device Manager the tape library is listed as an Unknown Medium Changer with a Microsoft driver.  If not change the driver using one of these procedures

How to uninstall the Original Equipment Manufacturer driver for the medium changer in a robotic library so as to make it "Unknown medium changer"

How to uninstall the Original Equipment Manufacturer driver for the medium changer in a robotic library so as to make it "Unknown medium changer" on Windows 2008 Server.

Also, make sure that the tape drive is using a Symantec driver

2) You can try tuning your tape drive.  See my article below

https://www-secure.symantec.com/connect/articles/t...

bakerjim5's picture

I was also having a speed issue - I was doing B2D to the SAN then Duplicating the job to tape from there - initially I had the SAN on Tier3 drive (7k speed). the B2D ran slow and the B2T even slower - after moving the SAN drives to Tier 1 (15K spped drives) the speed increased greatly.