Compression not working...

[Dave_Fortin]

I am working on getting a Veritas Backup Exec 9.1 solution implemented in our division, and was wondering if anyone has a solution to my problem.

Here is our scenario:

We have implemented a backup server with a rather large RAID 5 storage pool on it. BUE is installed on it and the departmental servers have the remote agents installed on them. Each night when we do a backup, the backups will be stored on the backup server, the following night, HP OpenView Data Protector will take the previous night’s backup and move it to tape. Therefore, we will always have the most recent set of backups on disk, on the network, thereby keeping the most recent backups available more quickly than having to go to tape to restore. In the event of a disaster, or if the backup server fails, we will go to tape to restore. When setting the options for a backup, there is an option in the BUE console under File> New Backup Job> then under the General heading, that asks for compression type. The options for compression are: None, Hardware, Software, and Hardware (if available, otherwise software). The manual says that the software compression BUE uses is called STAC.

When I kicked off a test backup job of a certain directory without the compression enabled, the size of the resulting .bkf file on the backup server was about 750MB. I checked the size of the directory on the server to be backed up, and they matched. Leading me to believe that the backup worked.

However, when I enabled the hardware (if available, otherwise software) option, and ran the same job, the backup resulted in a .bkf file of 750MB. It didn’t compress…

If anyone can shed some light on this situation, I would really appreciate it.

[John_McNamara]

The data that you are backing up may already be compressed. Items backup such as ZIP files are already compressed and cannot be compressed even more. Many tape drives use simple compression (at best they mark 2:1). Personally I've nevered backup anything better that 1.21:1 on a file server.
In most programs like WinZip, if there is compression already detected, the file is stored instread of second compression applied to it.

Try backing up data such as TXT docs (import a big file from Word and save it a text file). If this does not compress than you probably have a hardware or driver problem.
You can also check if there is a firmware update for your tape unit.

Hope this helps

[John_Chisari]

Change the job to use Software Compression - see how you go.

[Zerene_Sangma]

Hi Dave,

Did you try running the job with "software compression" ON.
Note that if your data is already in compressed form then no compression will be performed on an already compressed data.

Compression also depends on the data type. For example, it should be noted that certain types of data files (e.g. jpeg, gif, mp3, zip, mpeg, etc..) are already compressed due to their format hence cannot be compressed further.

Is the storage device on a RAID controller? If so, it may be the reason compression is not working. To isolate the issue, you can run a test backup using NTbackup and check if any compression is achieved.

[PTANK_2]

You will never see 2:1 compression unless you are backing up only text files. At least I have never seen it. Do what these people say, try software compression but, don't get your hopes up.
Side note, if you have your tape drive connected to the RAID controller, you will have bigger issues than compression.

Good luck
PTANK

[Dipti_Chinchole]

As a preliminary step please ensure that hardware compression is supported by the device you are using.


Please verify the compatibility of the storage device using the following compatibility list:



http://support.veritas.com/dsl/lists/device_ddProduct_BEWNT_media_all_prod1_NT9.htm


When using compression it is important to remember that the 2:1 compression ratio frequently assumed or stated in technical documentation is an ideal and seldom reached as a practical average.


Media capacity is calculated based upon past experience, once a tape has been read from beginning to end via backups to the tape and then when the tape is overwritten afterwards; or from a long erase or full catalog job.

Hence we request you to perform an erase operation on the tape and check. Also perform a full backup until the tape is filled for example if the tape capacity is 160GB then perform a backup of 160GB with overwrite option. Once the backup is completed and next time when the tape is inserted for backup, check the media capacity displayed.



Verify the compression ratio.

[Rohit_Sonawale]

Kindly update us on this issue.

[Harvey_Jader]

Hi Everyone,

I'm Using Veritas Backup Exec 9.1 running in Windows 2003 Server. Basically I have a SAN Storage that I need to backup on tape, MSL 6030 Tape Library with 200 GB capacity each I'm using the network to backup the files inside the SAN Storage because I have to backup 4 servers. For the past month, I tried to run the compression of the Veritas Backup Exec but it is not working. The actual capacity of the files are stored in the tape. I tried all the options given with respect to compression like software compression, hardware compression, hardware if not software compression and others. What seems to be the problem and any other special setup I need to do to make it work. Thanks

[Dave_Fortin]

Hi,

Thank you for the responses. I think the problem was with the fact that I had to patch my implementation of BUE. As soon as I did, I started getting compression on my backups. Right now, the compression ratio I am getting ranges between 1.4:1 and 1.6:1. I think this is perfectly acceptable. Thank you all so much for your responses and tips.
Best regards,
Dave Fortin