On Wed, 13 Jan 1999, Mr M S Aitchison wrote:
> [...] In some cases NT is better (the disk-write speed of its NTFS
> can be faster than ext2fs, but linux isn't limited to ext2fs of course).
while i agree with basically all your points, i have to take issue with
the above statement :)
i can see Linux saturate the disk for writes in a 4-8 disks in a properly
configured RAID setup, and i'm absolutely sure Linux goes to metal speed
in the 1-disk case:
-------Sequential Output-------- ---Sequential Input--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
500 8211 7.8 7749 6.5
this is a IBM DCAS-34330W disk, which _cannot_ do more than 7.7M/sec reads
and 8.2M/sec writes.
4 of these disks RAID0-ed together do:
-------Sequential Output-------- ---Sequential Input--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
500 34426 47.4 25452 22.0
as you can see, 32.4 is 4 times the write speed of the single-disk case
... (the read part scales with a factor of 3.5, all 4 disks are on a
single SCSI channel)
so i can see no, nil, zero, nada 'write performance on ext2fs' scalability
problems on Linux :)
-- mingo
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