No Data Compression after running the backup

[Rara_Amin]

Hi All,

Done the following troubleshooting to further isolate the issue but still failed:​

1. Disabled data encryption and data compression on the software portion and then ran the backup job but to no avail.
2. Restarted the Tape Autoloader which afterwards the Data compression went enabled but within running the backup job, it got disabled it again.
3. Disabled data compression from the Software portion (as recommended by HP to overrun data compression from the hardware portion) but still failed to work properly.   

     

Could someone explain the Compression ratio. As seen from the screenshot below, the ratio is 1.7:1

Hopefully someone could assist me. 

Thank you.

[pkh · Accepted solution]

A compression ratio of 1.7:1 is a good compression ratio. This means that 1.7MB of data backed up is compressed into 1MB. As a rule of thumb, the compression ratio of a typical mix of data types is expected to be between 1.2 to 1.4. What makes you think that you are not getting compression? You cannot do anything to improve your compression ratio. It is solely dependent on the type of data that you have

[Rara_Amin]

hi pkh,

Thank for advise but the 1st screenshot shown there is NO data compression because everytime i run a backup the data compression is being turned off.

Is it suppose to be a default setting? 

Thanks!

[pkh]

BE will turn on the compression as needed

[VJware]

Use only type of compression, either software or hardware.

If using hardware, then run a SCSI trace to verify if compression is indeed being enabled or not using this KB article - https://www.veritas.com/support/en_US/article.TECH50960

If hardware compression is getting disabled in the midst of the job, then run vendor diagnostics against the drive and maybe involve the hardware vendor as well.

[Colin_Weaver]

At the start of every job with hardware compression enabled Backup Exec sends the command to turn compression off and then slightly later sends the command to turn compresssion on again - this sequence can be captured in the debugs and tracer logs should you enable them.

In the past we have had issues where the compression on command is sent to the drive but does not take effect, as far as I am aware such issues have usually been something to do with the drive or HBA and cabling the drive is connected to. Unfortunately you do need to analyze tracer logs carefully to confirm that the command are being sent (especially as you wil see the off command first so then need to look for the on command)

This article contains some info.

http://www.veritas.com/docs/000033115

[Rara_Amin]

Hi All,

As for now, we managed to create a new backup and tried to set the compression type to both hardware (as seen in screenshot below) and software. 

However, after the creation of new backup and restarting the device, there is still no data compression and the size still remains the same at 2GB (screenshot below).

[VJware]

The screenshots show only hardware compression  being used resulting in 1:1 ratio.

What ratio do you get if the job is set to use only software compression ? And check the job log when software compression is used for the ratio.

[pkh]

What makes you think that the restore selection screen would show the amount of compressed data and not the amount of actual data backed up?

[Rara_Amin]

Hi All,

I'm still having this issues. I have check with my hardware vendor but they say the no hardware issues after the analysis it. I have log case with symantec but they keeping saying that my hardware it's having an issues as the data compression ratio shown 1:1. Is there any other suggestion to solve this?