From: enigma_3319@hotmail.com To: pgsql-performance@postgresql.org Subject: [PERFORM] Date: Fri, 2 Nov 2007 15:03:12 -0500
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In an 8 disk configuration where 2 are used for OS; 2 for xlog, and 4 for the database.. is this possible given Dell's possible configurations only allow 2 different RAID setups (SAS Raid1/Raid5)? I will also be contacting Dell, but does this require a more advanced RAID controller that supports 3 disk clusters (Raid 1 with 2 disks, Raid 1 with 2 disks, Raid 5 with 4 disks)? If I'm only allowed a 2:6 disk setup, where do you recommened placing the Xlogs; on the OS disks or on the databasae disks?
- Mark
On 11/1/07, Mark Floyd <mfloyd@evryx.com> wrote: Hello, Dell PowerEdge Energy 2950 (2) Quad Core Intel Xeon L5320, 2x4MB Cache, 1.86Ghz, 1066Mhz FSB 4GB 667Mhz Dual Ranked DIMMs, Energy Smart
PERC 5/i, x8 Backplane, Integrated Controller Card
Hard Drive Configuration: Integrated SAS/SATA RAID1/Raid 5
Hard Drive 1 (For Operating System): 36GB 10K RPM SAS 3Gbps 2.5-in Hot Plug HD Hard Drive 2 (For logs): 36GB 10K RPM SAS 3Gbps 2.5-in Hot Plug HD
Hard Drives 3,4,5,6 (In a RAID 5 Configuration): (4) 146GB 10K SAS 3Gbps Hard Drive, 2-5 inch, Hot Plug
If you can fit 8 drives in it, for the love of god add two more and mirror your OS and xlog drives ( I assume that's what you mean by drive 2 for logs). Running a server on non-redundant drives is not the best way to do things.
And if you can live on ~ 300 Gigs of storage instead of 450 Gigs, look into RAID-10 for your data array. RAID 10 is noticeably faster than RAID-5 for any database that sees a fair bit of writing activity.
It's overkill for our initial system but we are shooting for a system that allows for growth. If someone can let us know if we're on the right path or are shooting ourselves in the foot with this setup I'd appreciate it.
Other than the 8 cores, it's not really overkill. And depending on your usage patterns 8 cores may well not be overkill too.
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