Hello,
We are planning to moving most of our servers to ESX but before buying our SAN, we want to do some I/O stats to see if iSCSI is enough or if we have to go with FC. So I found a plugin for Nagios that can log I/O stats with iostat. So far it's fine with single disk/one partition servers, but on our Oracle Database 10g server, we have two drives in RAID 1 (/dev/sda) and 4 other drives in RAID 10 (/dev/sdb). When I query iostat, I get :
[root@golgoth ~]# iostat Linux 2.6.9-55.ELsmp (golgoth.acaiq-ctb.lan) 09/21/2009
avg-cpu: %user %nice %sys %iowait %idle 1.83 0.00 3.04 0.79 94.34
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sda 8.44 12.25 32.40 489731534 1295151278 sda1 0.00 0.00 0.00 21360 7478 sda2 6.60 80.90 44.41 3234128950 1775185432 sda3 0.05 0.20 0.23 7852212 9358056 sda4 0.00 0.00 0.00 2 0 sda5 41.16 38.59 95.20 1542695170 3805566528 sdb 2.84 72.63 28.91 2903208392 1155519494 sdb1 3.67 77.14 23.90 3083762026 955474128 sdb2 1.62 102.92 5.00 4114412086 200045262
So why sda have a lower TPS and bytes read/write than one of it's partitions (sda5, which is the root partition)? I guess I would have to collect the stats for each partitions to get what the total?