This varies greatly with the data, of course. I'm seeing compression ratios of 4:1 with email, which is mostly plain text with a lot of blank space characters. MIME attachments usually compress 2:1. Many binaries are already compressed, such as jpeg images, and do not compress any further. But on the general mix of client-owned data, I see more like 1.5:1.
Do client compression. They have more spare CPU cycles than your server does, and this also saves your network bandwidth. It also conserves space in your online disk storage pools. A study done by SPSS Inc. a few years ago showed that data compression was essentially free. The processor time it took to do the compression in a program's internal storage was less than the additional processor time it would have taken to handle the I/O for writing the larger, uncompressed file out. Just be prepared for that 200/400GB tape cartridge to hold only 200GB. Roger Deschner University of Illinois at Chicago [EMAIL PROTECTED] On Fri, 16 Apr 2004, Tom Kauffman wrote: >That depends -- on the data and on the client. > >I've got LTO-1 (100/200) GB tapes and drives. MS-Exchange Infostore backups >are compressed on disk and not decompressed by the client for backup - and I >get full tapes at 101 GB. On the other hand, my SAP/R3 (Oracle) database is >not compressed on the client -- and I get between 485 GB and 521 GB per >tape. > >So - you should get at least 190 to 200 GB per tape on the LTO-2; you MAY >get considerably more than 400 GB. We'll be going LTO-2 in five months, and >I'm looking forward to seeing how much SAP database I can fit on one tape. > >Tom Kauffman >NIBCO, Inc > >-----Original Message----- >From: Chandrashekar, C. R. (Chandrasekhar) >[mailto:[EMAIL PROTECTED] >Sent: Thursday, April 15, 2004 11:51 PM >To: [EMAIL PROTECTED] >Subject: LTO tape cartridge(200GB/400GB) stores data 500GB+. > >Hi, > >Just for clarification, I'm using LTO-Ult tape cartridge having capacity of >200GB/400GB, Tape library 3582L23 with two 3580-LTOG2 drives with firmware >38D0, and devclass was defined with device-type=LTO and Format=ULTRIM2C. Now >the tape is storing more then 500GB of data, Is it normal behavior. > >Thanks, >CRC, > >C.R.Chandrasekhar. >Systems Analyst. >Tivoli Certified Consultant (TSM). >TIMKEN Engineering & Research - INDIA (P) Ltd., Bangalore. >Phone No: 91-80-51362222. >Email:[EMAIL PROTECTED] > > > > >********************************************************************** >PLEASE NOTE: The above email address has recently changed from a previous >naming standard -- if this does not match your records, please update them >to use this new name in future email addressed to this individual. > >This message and any attachments are intended for the >individual or entity named above. If you are not the intended >recipient, please do not forward, copy, print, use or disclose this >communication to others; also please notify the sender by >replying to this message, and then delete it from your system. > >The Timken Company >********************************************************************** >
