Re: Benchmark: Dell/Perc 6, 8 disk RAID 10

Doug Knight wrote:
> All,
> I am in the process of specing out a purchase for our production
> systems, and am looking at the Dell 2950s as well. I am very interested
> to see where this thread goes, and what combinations work with different
> application loading types. Our systems will have one pair of
> heartbeat-controlled, drbd mirrored servers running postgresql 8.3, with
> a more write intensive, multiple writers and few readers application.
> The other similarly configured pair will have lots of readers and few
> writers. Our initial plan is RAID 10 for the database (four 300GB 15K
> drives in an attached MD1000 box) and RAID 1 for the OS (pair of 73GB
> drives internal to the 2950). PERC 6i for the internal drives (256MB
> battery backed cache), PERC 6E for the external drives (512MB battery
> backed cache). 8GB RAM, also dual Gig NICs for internet and
> heartbeat/drbd. Not sure which processor we're going with, or if 8GB
> memory will be enough. Keep the benchmarks coming.

We considered this configuration too. But in the end, we decided that by going with the 146 GB 2.5" drives, we could get 8 disks in the main box, and save the cost of the MD1000, which almost doubles the price of the system. We end up with a 546 GB RAID assembly, more than enough for our needs.

I think that 8 10K disks in a RAID 10 will be faster than 4 15K disks, and you only gain a little space (two 300GB versus four 146GB). So it seemed like we'd be paying more and getting less. With the battery-backed Perc 6i RAID, the advice seemed to be that the OS, WAL and Database could all share the disk without conflict, and I think the numbers will back that up. We're not in production yet, so only time will tell.

Craig

>
> Doug
>
> On Thu, 2008-03-13 at 04:11 -0400, Justin Graf wrote:
>> I recent just got a new server also from dell 2 weeks ago
>> went with more memory slower CPU, and smaller harddrives
>> have not run pgbench
>>
>> Dell PE 2950 III
>> 2 Quad Core 1.866 Ghz
>> 16 gigs of ram.
>> 8 hard drives 73Gig 10k RPM SAS
>> 2 drives in Mirrored for OS, Binaries, and WAL
>> 6 in a raid 10
>> Dual Gig Ethernet
>> OS Ubuntu 7.10
>> -----------------------------------------------
>>
>> Version 1.03
>> ------Sequential Output------ --Sequential Input-
>> --Random-
>> -Per Chr- --Block-- -Rewrite- -Per Chr-
>> --Block-- --Seeks--
>> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP
>> K/sec %CP /sec %CP
>> PriData 70000M 51030 90 107488 29 50666 10 38464
>> 65 102931 9 268.2 0
>>
>> ------Sequential Create------ --------Random Create--------
>> -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
>> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
>> 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
>> PriData,70000M,51030,90,107488,29,50666,10,38464,65,102931,9,268.2,0,16,
>> +++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++
>>
>> the difference in our results are interesting.
>>
>> What are the setting on the RAID card . I have the cache turned on
>> with Read Ahead
>>
>>
>> ---- Message from Craig James <craig_james(at)emolecules(dot)com>
>> <mailto:craig_james(at)emolecules(dot)com> at 03-12-2008 09:55:18 PM ------
>>
>> I just received a new server and thought benchmarks would be
>> interesting. I think this looks pretty good, but maybe there are
>> some suggestions about the configuration file. This is a web app,
>> a mix of read/write, where writes tend to be "insert into ...
>> (select ...)" where the resulting insert is on the order of 100 to
>> 10K rows of two integers. An external process also uses a LOT of
>> CPU power along with each query.
>>
>> Thanks,
>> Craig
>>
>>
>> Configuration:
>> Dell 2950
>> 8 CPU (Intel 2GHz Xeon)
>> 8 GB memory
>> Dell Perc 6i with battery-backed cache
>> RAID 10 of 8x 146GB SAS 10K 2.5" disks
>>
>> Everything (OS, WAL and databases) are on the one RAID array.
>>
>> Diffs from original configuration:
>>
>> max_connections = 1000
>> shared_buffers = 400MB
>> work_mem = 256MB
>> max_fsm_pages = 1000000
>> max_fsm_relations = 5000
>> wal_buffers = 256kB
>> effective_cache_size = 4GB
>>
>> Bonnie output (slightly reformatted)
>>
>> ------------------------------------------------------------------------------
>>
>> Delete files in random order...done.
>> Version 1.03
>> ------Sequential Output------ --Sequential Input-
>> --Random-
>> -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
>> --Seeks--
>> Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec
>> %CP /sec %CP
>> 16G 64205 99 234252 38 112924 26 65275 98 293852
>> 24 940.3 1
>>
>> ------Sequential Create------ --------Random
>> Create--------
>> -Create-- --Read--- -Delete-- -Create-- --Read---
>> -Delete--
>> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
>> /sec %CP
>> 16 12203 95 +++++ +++ 19469 94 12297 95 +++++ +++
>> 15578 82
>>
>> www.xxx.com,16G,64205,99,234252,38,112924,26,65275,98,293852,24,940.3,1,16,12203,95,+++++,+++,19469,94,12297,95,+++++,+++,15578,82
>>
>> ------------------------------------------------------------------------------
>>
>> $ pgbench -c 10 -t 10000 -v test -U test
>> starting vacuum...end.
>> starting vacuum accounts...end.
>> transaction type: TPC-B (sort of)
>> scaling factor: 1
>> number of clients: 10
>> number of transactions per client: 10000
>> number of transactions actually processed: 100000/100000
>> tps = 2786.377933 (including connections establishing)
>> tps = 2787.888209 (excluding connections establishing)
>>
>>
>>
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