Robin McDonald wrote:
So basically you raise 3 excellent points
... [snip]
2. ASM is a tool that runs on most OS oracle supports so to get the best performance out of it you must do some tuning which is OS & storage dependent. ASM is basically a "free" (once you've paid for your oracle licence) clusterable extent based filesystem. So while you could say there are other clusterable / extent based filesystems (veritas & SAMFS) neither are free.
My exposure to ASM was sufficiently traumatising that I decided that if I ever worked for Oracle I would have to re-engineer it so that it worked properly. (imnsho of course). The main problem I encountered with it had to do with scsi 2 / scsi 3 pgr reservations. As I recall it, ASM's method of reserving a lun was to run "dd" in a loop since "dd" is a command which does the same thing on all their target architecture. This was the problem for me, is that dd does not actually set a scsi2 pgre / scsi3 pgr key on the lun itself... and ASM basically left itself a window of opportunity to die horribly in the short period of time between one dd finishing and the next one starting. I *hope* that ASM has changed since I had to deal with it. James C. McPherson (daddy make the bad ASM man stop!) _______________________________________________ opensolaris-discuss mailing list [email protected]
