[CentOS] Filesystem for Maildir

Heitor A.M. Cardozo heitor at centralserver.com.br
Tue Dec 4 15:18:50 UTC 2007



-------- Mensagem original --------
Assunto: Re:[CentOS] Filesystem for Maildir
De: Christopher Chan <christopher at ias.com.hk>
Para: CentOS mailing list <centos at centos.org>
Data: terça-feira, 04 de dezembro de 2007 12:06:43
> Heitor A.M. Cardozo wrote:
>> Christopher Chan wrote:
>>>
>>> ext3 again takes the slowest performing title overall as 
>>> expected...in fact it appears not much as changed fs vs fs wise 
>>> since Bruce Guenter's tests. 
>> I agree but the values are more "acceptable" in comparision with 
>> others filesystems. On Bruce tests it shows a very bad performance 
>> for reading.
>
> Yes, reads are vastly improved at the cost of write performance. 
> Weird. XFS has like the best read response times too. XFS is looking 
> very good at the moment with just about the fastest performance in 
> everything. What io-scheduler is default on Centos 5? I assume you 
> prefer read performance to write performance. After all, it is for 
> maildir use. Have you tuned the box for read performance?
>
Initially this box is not tuned for read because I would to compare the 
results of tests on default configuration with other configurations.

The default io-scheduler on CentOS 5 is CFQ.

>>
>>> But I am surprised at the overall performance regressions in 
>>> comparison to 2.6.5/6 kernels with regards to deliveries vs amount 
>>> of writers.Heitor, you are using a 3ware 95xx or 96xx with BBU write 
>>> cache and write caching on right? How much RAM do you have for your 
>>> cache? How is your raid10 configured? I cannot believe a four disk 
>>> raid0 array can beat a software raid mirror of scsi disks as used by 
>>> Bruce Guenter.
>>>
>> 3ware 9650SE with BBU and write cache on.
>> Available memory: 224 MB
>> Bus Type/Speed: PCIe/2.5 Gbps
>> RAID10: 4 RAID1 subunits with MAXTOR STM3500630AS 500GB SATA2
>>
>
> Yup, that is four disks versus a single linux mirrored scsi array. 
> Write performance cannot be that horrible now can it?
>
Sorry, i forgot to say that the stripe size is set at 64Kb, not that 
this explain the bad write performance. I will configure and initilize 
array again and repeat one test to check.
>>>
>>> Thanks Heitor. Is the site down or something? I cannot access the 
>>> page....it is timing out.
>> The site is online now.
>>
>
> thanks.
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