compression ratio of litespeed

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compression ratio of litespeed

azad maratha

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Points: 1468
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August 4, 2010 at 8:02 pm

#103965

hi,
i am working on a script which searches if the backups are done or not by going to the backup folder.
and taking backups .but sometimes there is not enough space so i wanted to calculate the backup size.we are using litespeed.in litespeed command we r not mentioning the compression level.so it must be taking the default level.
a * database size=backup size
what is the value of a ?

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azad maratha Default port Points: 1468 More actions · Answer 1

why no one is answering the question?

is it irrevelant/stupid/unworthy?

is it posted in wrong section?

is it about litespeed?

i m not forcing anyone....but i should know if i m making any mistake ...so that i will not repeat it in future?

Lowell SSC Guru Points: 323518 More actions · Answer 2

well it's not a fixed ratio; a database with lots of varbinary/image/blob type data will have a less effective compression ratio than one that is mostly just text and numbers.

you should compare one normal backup of yours to one compressed backup, use that ratio, and use that as your "rule of thumb" / validation ratio.

a simple google search shows examples of 20:1, 40:1 and only 4:1 in the first five results for "sql litespeed compression ratio"

that's a pretty wide range of differences, so i think it's better to get a ratio related to your actual database.

Lowell

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Ali Bajwa Old Hand Points: 383 More actions · Answer 3

If I understand correctly, Azad wants to know the default compression level that Litespeed would use if we don't specify the value for @Compressionlevel which is one of the input parameter for the Litespeed extended stored procedure XP_DATABASE_BACKUP. I want to know the same and am looking for it. If I will find it, I will post it here as well. As SQLServerCentral is my favorite SQL website.

Steve Jones - SSC Editor SSC Guru Points: 736478 More actions · Answer 4

This lists the default level as 1, out of 11 possible levels. 0 is no compression, which is the same as a native backup.

https://support.quest.com/search/SolutionDetail.aspx?id=SOL14764

If you are looking for a percentage of compression, that is completely dependent on your data. More compression at higher levels is possible, at the expense of CPU and time.

The Red Gate SQL Backup tool includes an estimator for your database. I am not sure if Litespeed has something similar.

Disclosure: I work for Red Gate.

Ali Bajwa Old Hand Points: 383 More actions · Answer 5

That answers my question and I guess Azad's as well.

Thanks heaps Steve, you are a champion and thanks for writing good quality editorials.

Ali Bajwa Old Hand Points: 383 More actions · Answer 6

Sorry guys, forgot to add the link above to a good article about LiteSpeed Compression level:

http://troygallant.com/?p=155

Ali Bajwa Old Hand Points: 383 More actions · Answer 7

Quest's LiteSpeed version 5.0.1 and above has got "Backup Analyzer". It Helps you to find the optimal parameters for your database backup.

http://sqlserver.quest.com/pageloader.jspa?sbinPageName=litespeedfaq.htm&sbinPageTitle=FAQ%20on%20LiteSpeed