Poor sequential write performance.

[Naoki]

Why ohh why..

I have an old RedHat 6.2 box with 2.4.2 kernel and an IDE disk. When I 'wc' a file of about 100,000 text lines
it take under a second.

On my new RH 8.0 box with 2.4.18-14 kernel and SCSI disk it takes three seconds.

This is bizzare. Yes they are under the same load etc etc. They are both mounted with
noatime / nodirtime. What on earth is going on???

Any help most appreciated.


Look at this -

New machine :

time wc files*
6421 69607 894412 files
38806 420590 5394914 files.1
45227 490197 6289326 total

real 0m3.059s
user 0m2.543s
sys 0m0.064s

Old machine :

time wc files*
18628 201841 2597321 files
46603 505811 6501130 files.1
37122 402985 5201388 files.2
102353 1110637 14299839 total
0.25user 0.04system 0:00.38elapsed 76%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (115major+19minor)pagefaults 0swaps