On Thu, 2005-07-14 at 12:33 -0600, Andreas Dilger wrote: > On Jul 13, 2005 17:12 -0700, Jeffrey W. Baker wrote: ... > > The system is using an Areca hardware raid controller with 5 7200RPM > > SATA disks. The RAID controller has 128MB of cache and the disks each > > have 8MB. The cache is write-back. The system is Linux 2.6.12 on amd64 > > with 1GB system memory. ... > > Next I used pgbench to test parallel random I/O. pgbench has > > configurable number of clients and transactions per client, and can > > change the size of its database. I used a database of 100 million > > tuples (scale factor 1000). I times 100,000 transactions on each > > filesystem, with 10 and 100 clients per run. Figures are in > > transactions per second. > > > > ext3 jfs xfs > > 10 Clients 55 81 68 > > 100 Clients 61 100 64 > > > > Here XFS is not substantially faster but JFS continues to lead. > > > > JFS is roughly 60% faster than ext3 on pgbench and 40-70% faster on > > bonnie++ linear I/O. > > This is a bit surprising, I've never heard JFS as a leader in many > performance tests. Is pgbench at all related to dbench? The problem > with dbench is that for cases where the filesystem does no IO at all > it reports a best result. In real life the data has to make it to > disk at some point. ... > Try creating your ext3 filesystem with a larger journal, as Lustre does: > > mkfs -J size=400 ... > > size is in MB, 400 might be excessive for your setup - I'd be interested > in hearing where the "sweet spot" is for journal size. The latest e2fsprogs > use 128MB as the largest default size (up from 32MB) for large filesystems. The journal size doesn't seem to make any difference to pgbench, except that 256MB seems to be the worst. 400MB and 32MB are roughly equal on the pgbench workload. 400MB was the optimal journal size on the bonnie ++ workload. Perhaps it is silly to benchmark a database with its journal files on a journalling filesystem, but here is the result. journal pgbench tps bonnie++ MB/s -------------------------------------------------------- size | mode | 1 | 10 | 100 | write | rewrite | read -------------------------------------------------------- 32 journal 57 35 112 32 ordered 28 51 57 83 33 101 32 writeback 34 70 88 57 31 103 64 journal 55 33 113 64 ordered 29 52 61 84 33 100 64 writeback 32 69 87 59 31 100 128 journal 52 33 109 128 ordered 32 54 62 86 34 102 128 writeback 34 70 88 61 32 102 256 journal 54 30 110 256 ordered 28 51 60 90 34 106 256 writeback 29 64 79 59 31 104 400 journal 52 28 108 400 ordered 26 49 59 89 33 104 400 writeback 32 70 87 60 32 101 --- ext2 105 118 32 107 -jwb _______________________________________________ Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
