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Compression Type

Created: 19 Mar 2013 • Updated: 15 Apr 2013 | 7 comments
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I am a newbie to backups and have a simple query on Compression Type. We have symantec backup exec 2010 and a Dell LTO5 tape library. I want to backup a drive(2 TB) on a server. The files are index files. What is the compression type from below 4 which i need to use to complete the job in the fastest time ?

1] None

2] Software

3] Hardware [if available,otherwise none]

4] Hardware[if available,otherwise software]

Thanks !

Operating Systems:

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CraigV's picture


That's like asking how long is a piece of string?

There are a lot of other things to consider, including: speed of your LAN/WAN, type of data being backed up; spec of the media server etc.

I always chose #4 on your list. If the device couldn't do it, then softwarr compression (using the media server's resources) would bring on some sort of compression.

Your data type being backed up at the time it is sent to the tape may/may not be compressed, and the amount of compression is also dependent on this data.


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sujit1215's picture

Thanks Craig,i know the question is very generic but iam just testing to determine which compression type suits best for me. I tried to run the job yesterday with " Hardware [if available,otherwise none] " and it took a long time. I am not sure if it did the compression. Below is the output of the job log.

Backed up 87 files in 21 directories.
Processed 836286184519 bytes in  9 hours,  36 minutes, and  22 seconds.
Throughput rate: 1384 MB/min
Compression Type: Hardware
CraigV's picture

...check the tape used in the Media tab of will show you the compression ratio it got for all the data backed up.


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sujit1215's picture

The compression i see for the tape used is 1:2:1

sujit1215's picture

Dont know what the compression ratio indicates?

CraigV's picture means you're getting 1.2 x the native storage capacity of an LTO5 drive...approximately 1.8TB on the tape.

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teiva-boy's picture

Option #3 is the most common setting in 90%+ of environments.  None of the options will generally speed up backups.

Most any tape drive built in the last 10yrs can do compression in hardware.  And you want to leverage that if you can.

Now the dirty secret to LTO5 is that you NEED to write at a minimum speed in your case around 50MB/s.  Since you are using hardware compression, you must actually write to that drive at a minimum of around 60MB/s (3600MB/min) since you are getting 1.2:1 compression already.

Odds are you are not getting anywhere close to that speed, and are now shoe-shining that tape and the drive, causing premature wear and failure.

The only way to aleviate that, is to write to disk FIRST, then duplicate off to tape.  Of course your disk has to be able to read at 60+MB/s.  Which isn't that hard with a RAID5/RAID6 array with at least 7 spindles.

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."