Joni, Generally you can look to top or a similar utility to monitor compression impact on processors during backups.
Compression works by creating a "dictionary" of redundant chunks of bytes, and replacing repeats of those data chunks in the file with pointers back to the dictionary. Dictionary and compressed data are then saved in the file. So the more redundant your data, the more compressed it can be (I had to hand code this once in the early Java days). We have gone both ways on compression in our client sites. There are really three things that make the most difference. Hardware/OS: Big processors and lots of memory, little load means compression has no impact on local performance. If there is no impact on the work being done by the client during backup, compression good (I have seen a Novell server become a swirling vortex of doom when compression was turned on). Network: Small pipe or saturated pipe, compression good. Big pipe, not so much. Data Backed Up: Sparse data, such a databases, text files, files with lots of repeating data chunks, compression good. Lots of images (compressed formats), compressed archives, encrypted files all have few repeating data chunks, compression bad. For example, when we compress down data we use in our web services (XML format), we get 10 to one--but there are a lot of repeats (xml tags, and strings). So, depending on the hardware configuration, network, and data type compression will cut time. Outside of the Novell experience, compress was painless during normal ITSM operation. You can expect to save 10-50% time on the Oracle box if you have the processor/memory (and you database is not full of binary data), check if the Lotus files are compressed or encrypted, that will make a difference. One test could be to take a representative set of files and gzip them, and see what you save in size, since that will be similar to what is sent over the network. --David Moring www.backupinsight.com 512-782-HELP Joni Moyer wrote:
Hello All! I am considering turning client compression on for our Lotus Notes Domino and Oracle servers. What should be looked at/considered before client compression is turned on? How do you monitor the impact of turning client compression on? Any ideas/suggestions are appreciated! Thanks! ******************************** Joni Moyer Highmark Storage Systems, Storage Mngt Analyst III Phone Number: (717)302-9966 Fax: (717) 302-9826 [EMAIL PROTECTED] ********************************
