Horton

Thread

  1. configuring new server / many slow disks?

    Axel Rau <axel.rau@chaos1.de> — 2007-03-08T11:30:45Z

    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.

Current configuration is:
- Tyan S3992G3NR
- 2 x Opteron 2212 (2GHz)
- 8 GB RAM (DDR2-667)
- ARC-1261ML with 1GB and BBU
- 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)?
Should I revert to a single-CPU to prevent from oscillating cache  
updates between CPUS?
Anybody experience about NUMA stuff with FreeBSD?

Do you have any suggestions to enhance the configuration, staying at  
cost level?
Please advice.

Axel
---------------------------------------------------------------------
Axel Rau, ☀Frankfurt , Germany                       +49 69 9514 18 0

  2. Re: configuring new server / many slow disks?

    Axel Rau <axel.rau@chaos1.de> — 2007-03-09T11:22:13Z

    Am 08.03.2007 um 12:30 schrieb Axel Rau:

> Can I expect similar performance as 5 drives at 10k rpm (same costs)?
> Should I revert to a single-CPU to prevent from oscillating cache  
> updates between CPUS?
> Anybody experience about NUMA stuff with FreeBSD?
>
> Do you have any suggestions to enhance the configuration, staying  
> at cost level?
> Please advice.
No response at all?
Does this mean, my config sounds reasonable?

Axel
---------------------------------------------------------------------
Axel Rau, ☀Frankfurt , Germany                       +49 69 9514 18 0

  3. Re: configuring new server / many slow disks?

    Richard Huxton <dev@archonet.com> — 2007-03-09T11:42:39Z

    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?
How big do you expect the databases to get? 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.

> - 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.

> 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.
-- 
   Richard Huxton
   Archonet Ltd

  4. Re: configuring new server / many slow disks?

    Axel Rau <axel.rau@chaos1.de> — 2007-03-09T17:39:33Z

    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
---------------------------------------------------------------------
Axel Rau, ☀Frankfurt , Germany                       +49 69 9514 18 0

  5. Re: configuring new server / many slow disks?

    Scott Marlowe <smarlowe@g2switchworks.com> — 2007-03-09T19:28:34Z

    On Fri, 2007-03-09 at 11:39, Axel Rau wrote:
> 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).

I'd benchmark it to make sure.  20 updates and 50 inserts per second on
simple tables with small amounts of data?  No problem.  Lots of big
bytea / blob data getting inserted and read back out?  Not so sure.

Certainly your BBU RAID controller will help, and lots of slower hard
drives is generally far better than a few faster drives.

The only way to know is to make up a test and see how it performs.