On Mon, Aug 12, 2002 at 08:03:34PM -0700, Andrew Morton wrote:
> Adam Kropelin wrote:
> > Actually, I'm running an FTP server on the testbed machine and pushing the
> > data from a client on another (much faster) machine. I straced the server
> > (redhat wu-ftpd2.6.1-20) and it looks like 8 KB reads/writes.
> >
>
> OK, tried that against a slow disk (13 megs/sec write bandwidth). 2.5.31,
> defalt writeback settings.
>
> ext3 is misbehaving:
> and takes 86 seconds.
>
> When the server is writing to ext2, it is good:
> and the transfer takes 54 seconds, which is wirespeed.
>
> Are you _sure_ it was bad with ext2?
Yes.
[root@devbox adk0212] mount
/dev/hda3 on / type ext2 (rw)
none on /proc type proc (rw)
/dev/hda1 on /boot type ext2 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
none on /dev/shm type tmpfs (rw)
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
0 1 1 120 4360 0 141132 0 0 0 9804 6775 564 0 45 55
0 1 1 120 4344 0 141132 0 0 0 0 1083 20 0 0 99
0 0 0 120 4364 0 141116 0 0 0 40 2098 156 0 11 89
0 0 0 120 4384 0 141368 0 0 0 4 7013 594 0 52 47
0 0 0 120 4360 0 141416 0 0 0 0 6914 589 1 56 43
0 1 1 120 4464 0 140856 0 0 0 15420 6235 520 0 42 58
0 1 1 120 4456 0 140856 0 0 0 3240 1094 36 0 2 98
1 0 0 120 4428 0 140844 0 0 0 52 1151 70 0 4 96
1 0 0 120 4440 0 141356 0 0 0 4 6810 541 1 42 57
0 0 0 120 4464 0 141320 0 0 0 0 6894 553 1 40 58
0 1 1 120 4396 0 140840 0 0 0 15508 6018 466 0 40 59
0 1 1 120 4388 0 140840 0 0 0 1608 1093 57 0 2 98
0 0 0 120 4404 0 140832 0 0 0 52 2350 165 0 12 87
0 0 0 120 4460 0 141380 0 0 0 4 7040 564 1 42 57
1 0 0 120 4356 0 141372 0 0 0 4 7073 570 1 45 54
0 1 1 120 4360 0 140916 0 0 0 15404 5541 437 1 36 63
0 1 1 120 4356 0 140916 0 0 0 2832 1084 55 0 1 99
0 0 0 120 4356 0 140904 0 0 0 48 1614 125 0 8 91
0 0 1 120 4380 0 141412 0 0 0 4 6888 552 1 43 56
1 0 0 120 4232 0 141476 0 0 4 0 6857 556 1 40 58
0 1 1 120 4352 0 140988 0 0 0 13700 5148 449 0 35 65
Is it possible that the darn thing is mounted ext3 even though fstab and mount
agree that it's ext2?
> How long does
>
> dd if=/dev/zero of=foo bs=1M count=600 ; sync
>
> take against that disk?
1m 23s (I said it was a slow disk ;)
Even during that, the writeout was inconsistent (but a lot better than during
the FTP transfer):
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
0 1 3 1784 2180 0 141072 0 0 0 5220 1070 19 0 6 93
0 1 2 1784 2248 0 141020 0 0 0 8064 1066 23 0 8 92
1 0 3 1784 2296 0 141008 0 0 0 8436 1132 36 0 12 87
0 1 3 1784 2300 0 141004 0 0 0 6828 1072 164 0 24 75
1 0 2 1784 2988 0 140336 0 0 0 4664 1071 144 0 21 79
1 0 2 1784 2616 0 140700 0 0 0 12944 2688 102 0 5 95
0 1 3 1784 2296 0 141036 0 0 0 10048 1076 125 1 21 78
0 1 1 1784 3284 0 140048 0 0 4 5504 1064 143 0 19 80
0 1 1 1784 3284 0 140048 0 0 0 0 1064 51 0 1 99
0 1 1 1784 3284 0 140048 0 0 0 0 1058 23 0 1 99
1 1 3 1812 2312 0 141236 0 28 0 22892 2495 131 0 10 90
0 2 3 1812 3204 0 140340 0 0 4 7736 1065 81 0 25 75
0 2 3 1812 3204 0 140340 0 0 0 3848 1062 52 0 9 90
0 2 3 1812 3204 0 140340 0 0 0 7696 1059 50 0 2 98
0 1 3 1812 3196 0 140336 0 0 4 3976 1061 58 0 20 80
0 1 3 1812 3312 0 140208 0 0 0 7944 1065 25 0 4 96
0 1 2 1812 3308 0 140208 0 0 0 3844 1065 32 0 1 99
0 1 2 1812 3308 0 140208 0 0 0 2956 1056 43 0 3 97
0 1 2 1812 3268 0 140248 0 0 4 5548 1059 64 0 5 94
0 1 2 1812 3268 0 140252 0 0 0 236 1065 56 0 4 96
0 1 2 1812 3268 0 140252 0 0 0 0 1058 42 0 1 99
(all of the above discussion was 2.5.31 stock with default writeout settings)
I've been trying these sorts of tests on this machine for over a year now,
with various disk subsystems, and I have *never* seen anything as nice and
consistent as the ext2 writeout you quoted. Maybe this machine is cursed.
--Adam
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:30 EST