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sujit1215's avatar
sujit1215
Level 3
12 years ago
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Compression Type

Hi,

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 !

  • 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.

     

  • Hi,

     

    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.

    Thanks!

  • 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
    


     

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

    Thanks!

  • 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.

     

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