Optimal File System config for 2.5TB RAID5

Josh Paetzel jpaetzel at FreeBSD.org
Tue Sep 30 12:58:01 UTC 2008

Hash: SHA1

Danny Do wrote:
> Hello,
> I am building a 6x500GB SATA HARDWARE RAID5 storage server to
> - Store large files, 10BM~1GB/file
> - Handling 500+ concurrent connections
> - Transfer rate around 100~200Mbit/s
> I am thinking of using the patch from Wojciech Puchar to reduce hard drive
> data seek in order to handle large number of concurrent connections whilst
> outputting 100~200Mbit/s.
> patch /usr/src/sys/sys/param.h
> #ifndef DFLTPHYS
> #define DFLTPHYS        (1024 * 1024)   /* default max raw I/O transfer size
> */
> #endif
> #ifndef MAXPHYS
> #define MAXPHYS         (1024 * 1024)   /* max raw I/O transfer size */
> #endif
> #ifndef MAXDUMPPGS
> To store files greater than 10MB, I come up with the following proposal for
> my File System:
> - UFS2
> - Soft Update  Enable
> - block-size   1,048,576
> I am not completely sure what advantage I got from this configuration but I
> am pretty sure that FSCK is much quicker with 1M file system block-size. 
> Is there any other thing I need to consider in term of performance and
> reliability?
> I hope that this system will perform much better than my current 6x300GB
> SCSI 10K RPM system.
> Appreciate any advice,
> Danny

Why do you think slower drives using an interface that has known
problems handling concurrent connections will be faster than faster
drives using an interface designed for concurrency?

Based on my experiences with SATA vs. U160/U320 SCSI or SAS your likely
outcome is to see a marked decrease in performance.  I'd be interested
to hear your results.

- --

Josh Paetzel

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