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Expecting faster backup rates from iSCSI san into Backup exec 2012

Created: 07 Dec 2012 | 8 comments

Hi everyone, 

I have a Dell MD3000i iSCSI SAN (14 600GB 7200K SAS drives in RAID 5)

directly connected (1 Gig ethernet) to a Dell Poweredge R710 server with Backup exec 2012 installed to it.

I also have a Dell TL2000 tape library with an LTO5 drive connected to the Poweredge R710 using SAS using Symantes supplied drivers..

The LTO5 drive is configured with a 64KB Block size, 1MB Buffer size and everything else set to default.

A full backup of my data (around 8TB) takes approx 4 days on the TL2000, with an average data rate of 950.00 MB/min reported in backup exec.

I was expecting higher transfer speeds and am having trouble determining the speed bottleneck.  Can anyone help determine why it's taking so long to backup 8TB data onto LTO5?

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ZeRoC00L's picture

How fast can you copy data from the disks ?
If the server has local disks, copy some data from the SAN to this disk, and see what the transfer-rate is.
If you don't have local disks, install a tool to create a RAM-drive, and again copy some data from the SAN to disk.

Backup exec will never get any faster then you get the data from disks.

If this response answers your concern, please mark it as a "solution"

ZeRoC00L's picture

Windows 2008(R2) can display this information when you click on the more details button during a copy dialog. Make sure to copy a folder/folders with a representative amount of data !

If this response answers your concern, please mark it as a "solution"

piasukIT's picture

I transferred a 4GB file and the rate was about 50MB/second on average

ZeRoC00L's picture

Also copy some smaller files/multiple folders, also the size of app. 4GB and see what you get.
One large file is always faster the multiple small files.

If this response answers your concern, please mark it as a "solution"

piasukIT's picture

OK, multiple small files takes it down to about 15MB/Sec but it's not an accurate test at the moment as I have a backup job running.

I'll test again after the weekend once the backup job completes.

ZeRoC00L's picture


Also check if there are no other jobs running during the backup.
For example a virusscan, or something else that may cause lots of I/Os on the storage system.

If this response answers your concern, please mark it as a "solution"

teiva-boy's picture

1GbE.  Thats your bottleneck.  You need to be using MPIO, multiple GbE links, and from that, MULTIPLE concurrent backup jobs to leverage what MPIO brings to the table.  50MB maybe up to 80MB/s on an MD series array with 7200RPM disks is about par for the course.  That is an entry level SAN which actually started life as a DAS.

Now the above helps you with backing up to disk.  Unless your 8TB is on the MD3xxx SAN?

Then what you need to play with is the tape settings to see what is most optimum for you.  128KB over 64KB does help on LTO4/5 depending on the tape drive manufacturer (Not the library vendor).  You just have to play and see what improves.

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