-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I'm running Postgres 8.3.7 on Solaris 10 x64, using VxFS/VxVM 5.0 MP3. I'm trying to determine the best storage configuration for my workload, so I ran some tests of Postgres performance with various combinations of VM and filesystem. What I noticed was that when all other factors were the same, running on VxVM was nearly twice as slow as running on a plain disk. My configuration was a VxFS filesystem mounted at /sql, 'noatime,cio', and another mounted at /sql/pg_xlog, 'noatime,cio,mincache=direct,convosync=direct'. This forced direct I/O for the WAL. Without VxVM, these filesystems were on plain disk slices. With VxVM, I added the single disk to a diskgroup and created two volumes on it for the filesystems, layout=concat, with the default options. The backend storage is a 14-disk RAID10 using an internal RAID card (Sun StorageTek STK-RAID-INT), with 256MB battery-backed write cache. The system has 32GB RAM and nothing apart from Postgres was running on it during the test. The same postgresql.conf was used for both tests; I configured 256MB of shared_buffers and 20 checkpoint_segments. The benchmark I'm using is a database import tool called "osm2pgsql", with a subset of our actual workload. Without VxVM, the import completed in 2 hours, 34 minutes. With VxVM, it took 5 hours 7 minutes. Has anyone else tested Postgres on VxVM and noticed such a large performance hit? - river. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (HP-UX) iEYEARECAAYFAksWK6kACgkQIXd7fCuc5vIJowCfUVLjDQ7R34n4QIls4Uenahoq lNMAn3CO7zr+HIwirKZMl3YRtiFdMaY+ =/kND -----END PGP SIGNATURE----- -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
