"Benno" <0@0.invalid> wrote in message news:40fb75f1$0$284$4d4ebb8e@news.nl.uu.net
> Due to applications as the SAP client and AutoCAD 2002 our users roaming
> profiles contain thousands of very small files. I have noticed that the
> average transfer rate of those small files (~350Bytes in size) over the
> network is extremely slow compared to normal to large sized files (300KB
> up to a few MB). With the normal sized files I'm seeing transfer rates
> to the workstations of 4MB to 15MB per second, with the small files this
> drops to as low as 75KB per second with an average of ~200KB per second.

512 bytes (one sector) or 4 kB (one cluster) reside in a single 64kB
stripe so it transfers at single drive speed.

At an STR of 51MB/s this file transfers in .1 ms or .4 ms

With an average access time of 12 ms your average transfer rate is from
(.1/12.1)*51MB/s 420kB/s to 1.65MB/s (.4/12.4)*51MB/s

Your 350 byte file may run at 350/4096*1.65 MB/s = 400KB/s.
(And yes, because of that huge difference in access time and actual trans-
fer time it is trivial whether the disk system reads a sector or a cluster).

>
> The roaming profiles are stored on a RAID5 logical drive with a 64KB
> stripe size

Any file of 64kB is now a small file.
Whether it is read in parallel now depends on it being fragmented and how.

> (I think this is the maximum for the Smart Array 5300
> controller) and the NTFS partition is formatted with the default 4KB
> cluster size. The Array Controller cache is configured 25% read / 75%
> write to compensate for the RAID5 slower writes.
>
> The server is a Windows 2000 SP4 machine, the workstations are NT4 SP6a.
> The network is 100Mb switched with a 1000Mb connection to the fileserver.
>
> Is there anything I can do with the RAID stripe size or the cluster size
> to increase the throughput of those small files without affecting
> transfer speed the normal sized files to much?

Little to none.

>
> Are there any benchmark programs that I can use to test this?
>
> Could the TCP/IP Windows size be an issue here?

Maybe, for the difference between your 75kB/s and my 400kB/s.

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