Compression is done from the channel interface card to the VTS cache. Compression is then done again from the VTS cache to the back end drive without much, if any, gain in compression. Check the SMF 94's for these values.
Victor Zhang <[EMAIL PROTECTED]> Sent by: IBM Mainframe Discussion List <[email protected]> 09/29/2006 01:56 AM Please respond to IBM Mainframe Discussion List <[email protected]> To [email protected] cc Subject Logical volume in IBM VTS,compressed or not? Hello list, I have a dumb question regarding logical volumes written to IBM's VTS, is the data compressed or not? IBM recently announced next generation of VTS:TS7700, from its production description, only usable capacity(raw disk capactiy - meta data overhead).When it is talking about backend tape drives, it only mentions that TS1120 or 3592 can compress data at a ratio of about 3:1. That raises my confustion: is data written to VTS cache compressed or not? Thanks in advance. Regards Victor ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
