Am 09.03.2007 um 12:42 schrieb Richard Huxton:
Axel Rau wrote:
Hi performers,
after following this list for a while, I try to configure a
database server with a limited budget.
Planned are 2 databases
- archiveopteryx - http://www.archiveopteryx.org/sql-schema.html
- ERDB - https://www.chaos1.de/svn-public/repos/network-tools/ERDB/
trunk/database/ERD.pdf In peak times I expect something like
- 50 inserts
- 20 updates
- 200 selects
per second.
Presumably with multiple clients, not just one extremely busy one?
Multiple clients do mainly selects (the IMAP users), few mailservers
are busy and do mainly inserts and updates.
How big do you expect the databases to get?
Up to 1 TB. The 1st DB is an IMAP message store, which keeps Mime
message parts as byteas in one table (bodyparts).
That'll affect the next point.
Current configuration is:
- Tyan S3992G3NR
- 2 x Opteron 2212 (2GHz)
- 8 GB RAM (DDR2-667)
Depending on the amount of data you've got to deal with, it might
be worth trading disks/cpu for more RAM.
- ARC-1261ML with 1GB and BBU
OK, so you can turn write-caching on. That should let you handle
more updates than you need. You probably don't need so much RAM on
board either, unless each update has a lot of data in it.
updates not, but inserts may have 10-20 MBs.
- 16 Seagate ST3250820NS (250GB, 7200 rpm, 8GB, with perpendicular
recording)
1 raid 1 for OS (FreeBSD) and WAL
1 raid 0 with 7 raid 1 for tablespace
Can I expect similar performance as 5 drives at 10k rpm (same costs)?
The main question is whether you're going to need to hit the disks
often. If you can get to the stage where the working-set of your
DBs are all in RAM you could sacrifice some disks. If not, disk I/
O dominates.
Because of the table with the blobs, I need the many disks.
Perhaps this table would be worth of on an own table space / raid 10
set.
Should I revert to a single-CPU to prevent from oscillating cache
updates between CPUS?
Anybody experience about NUMA stuff with FreeBSD?
Sorry - I know nothing about FreeBSD.
That any use - I didn't bother to reply before because I couldn't
help with the BSD stuff, and it's always guesswork with these sorts
of questions.
--
Axel
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Axel Rau, ☀Frankfurt , Germany +49 69 9514 18 0
