> We are trying to decide which 3390 model to configure in our incoming > storage device (probably emc but could be shark). The point of interest is > which model provides the least amount of 'wasted' space due to overhead > requirements.
The flippant smart-ass answer is "configure it as FCP-based FBA storage and forget the 3390 emulation if you plan to use it for Linux data", but the question is a good one. If you're running under VM, it matters a lot less what the physical size of the disk volumes are. Minidisks can be any size less than or equal to the physical volume size, so bigger physical volumes are usually simpler to manage from a tool-management perspective (fewer updates to the DIRMAINT config), but do impose a performance penalty for access time. We find mod 9s are good compromises, but you may want some mod-27s or mod-54s for DBMS apps or other things that you're going to LVM together to get bigger hunks of space. There are tradeoffs with # of spindles vs capacity that play out in application performance and manageability, too -- remember, only 1 I/O outstanding per subchannel id for ECKD. Depending on the access characteristics, your guests may benefit from LVMs created on multiple physical volumes that map to different areas in the storage box, or the storage box may try to be too smart for it's own good and "optimize" away any advantage. Actual data placement will be worth examining. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
