>> On Mon, 21 Aug 2006 08:43:26 -0700, "Gill, Geoffrey L." <[EMAIL PROTECTED]> >> said:
> To be more clear. The 4 D40's are a mixture of database, logs and > disk pools. One VG for database, one for mirrored database and one > for data storage pools. Mkay; good. :) What size disks? were these the same disks as on your previous setup? When I moved from 9G to 18G spindles for databases, I found that having DB volumes fill the spindle blew my performance for ( I inferred ) contention reasons. You said 120GB; I'll presume that's available space. Even with 36G SSA, that's just 4 volumes, 4 threads with which DB work can be done. For comparison's sake, with 316GB of aggregate available databse space, I have 35 volumes defined, mostly on 18G spindles. Now, I'm in a very different environment, 11 servers on that piece of hardware. But even so, you get the sense. My largest single DB, ~70G, has 8 (mirrored) volumes. I think it possible that you will see performance improvement if you merely cut your DB volume size. Don't go nuts, there's certainly a performance trainwreck at the other side of the scale, too: dozens of DB vols per spindle is Right Out. But you might consider 2 or 3 if you're at 36G, maybe even more if you're at 72. > Four full D40's just for a database would be quite unnecessary. Agreed, though I wasn't visualizing that; I was visualizing one JBOD RAID (raid-0?) with LVs carved out for whatever purposes. > No raid anywhere, all raw disk consisting of one LV per disk no > matter if it is database, log or disk pool related. Digression: strongly suggest RAID for the data pools. 5-disk RAIDs seem to be good performance for SSA, and then you have a hot spare 1/drawer. Pedantic comment: If you're doing LVM with unraided disks, I'm not sure JBOD applies. Isn't that a RAID term-of-art? Gratuitous label: things come in threes. - Allen S. Rout
