Thread: Setup of four 15k SAS disk with LSI raid controller
I have a server with 32GB ram, one intel E3-1245 and four 15k SAS disks with a BB LSI MegaRaid controller. I wan't the optimalperformance for my server, which will be pretty write heavy at times, and less optimized for redundancy, as my datais not very crucial and I will be running a streaming replication along side. Now what would you prefer: 1) 3 disks in RAID 0 containing PGDATA + 1 containing SYSTEM and WAL 2) All four in RAID 10 containing both PGDATA, SYSTEM AND WAL 3) 2 disks in RAID 1 containing PGDATA + 2 disks in RAID 1 containing SYSTEM and WAL 4) Something different?
raid0 tends to linear scaling so 3 of them should give something close to 300% increased write speed. So i would say 1. but make sure you test your configuration as soon as you can with bonnie++ or something similar
On Wed, Mar 13, 2013 at 7:43 PM, Niels Kristian Schjødt <nielskristian@autouncle.com> wrote:
I have a server with 32GB ram, one intel E3-1245 and four 15k SAS disks with a BB LSI MegaRaid controller. I wan't the optimal performance for my server, which will be pretty write heavy at times, and less optimized for redundancy, as my data is not very crucial and I will be running a streaming replication along side.
Now what would you prefer:
1) 3 disks in RAID 0 containing PGDATA + 1 containing SYSTEM and WAL
2) All four in RAID 10 containing both PGDATA, SYSTEM AND WAL
3) 2 disks in RAID 1 containing PGDATA + 2 disks in RAID 1 containing SYSTEM and WAL
4) Something different?
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Den 13/03/2013 kl. 19.15 skrev Vasilis Ventirozos <v.ventirozos@gmail.com>:
A 5. option could also be to simply have all 4 disk in a RAID 0 containing all PGDATA, SYSTEM and WALraid0 tends to linear scaling so 3 of them should give something close to 300% increased write speed. So i would say 1. but make sure you test your configuration as soon as you can with bonnie++ or something similarOn Wed, Mar 13, 2013 at 7:43 PM, Niels Kristian Schjødt <nielskristian@autouncle.com> wrote:I have a server with 32GB ram, one intel E3-1245 and four 15k SAS disks with a BB LSI MegaRaid controller. I wan't the optimal performance for my server, which will be pretty write heavy at times, and less optimized for redundancy, as my data is not very crucial and I will be running a streaming replication along side.
Now what would you prefer:
1) 3 disks in RAID 0 containing PGDATA + 1 containing SYSTEM and WAL
2) All four in RAID 10 containing both PGDATA, SYSTEM AND WAL
3) 2 disks in RAID 1 containing PGDATA + 2 disks in RAID 1 containing SYSTEM and WAL
4) Something different?
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Its better to split WAL segments and data just because these two have different io requirements and because its easier to measure and tune things if you have them on different disks.
Vasilis Ventirozos
On Wed, Mar 13, 2013 at 8:37 PM, Niels Kristian Schjødt <nielskristian@autouncle.com> wrote:
Den 13/03/2013 kl. 19.15 skrev Vasilis Ventirozos <v.ventirozos@gmail.com>:A 5. option could also be to simply have all 4 disk in a RAID 0 containing all PGDATA, SYSTEM and WALraid0 tends to linear scaling so 3 of them should give something close to 300% increased write speed. So i would say 1. but make sure you test your configuration as soon as you can with bonnie++ or something similarOn Wed, Mar 13, 2013 at 7:43 PM, Niels Kristian Schjødt <nielskristian@autouncle.com> wrote:I have a server with 32GB ram, one intel E3-1245 and four 15k SAS disks with a BB LSI MegaRaid controller. I wan't the optimal performance for my server, which will be pretty write heavy at times, and less optimized for redundancy, as my data is not very crucial and I will be running a streaming replication along side.
Now what would you prefer:
1) 3 disks in RAID 0 containing PGDATA + 1 containing SYSTEM and WAL
2) All four in RAID 10 containing both PGDATA, SYSTEM AND WAL
3) 2 disks in RAID 1 containing PGDATA + 2 disks in RAID 1 containing SYSTEM and WAL
4) Something different?
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On 03/13/2013 11:45 AM, Vasilis Ventirozos wrote: > Its better to split WAL segments and data just because these two have > different io requirements and because its easier to measure and tune > things if you have them on different disks. Generally speaking you are correct but we are talking about RAID 0 here. JD -- Command Prompt, Inc. - http://www.commandprompt.com/ PostgreSQL Support, Training, Professional Services and Development High Availability, Oracle Conversion, Postgres-XC @cmdpromptinc - 509-416-6579
Den 13/03/2013 kl. 20.01 skrev Joshua D. Drake <jd@commandprompt.com>: > > On 03/13/2013 11:45 AM, Vasilis Ventirozos wrote: >> Its better to split WAL segments and data just because these two have >> different io requirements and because its easier to measure and tune >> things if you have them on different disks. > > Generally speaking you are correct but we are talking about RAID 0 here. So your suggestion is? > JD > > -- > Command Prompt, Inc. - http://www.commandprompt.com/ > PostgreSQL Support, Training, Professional Services and Development > High Availability, Oracle Conversion, Postgres-XC > @cmdpromptinc - 509-416-6579 > > > -- > Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance