Date: Wed, 04 Feb 1998 00:02:01 -0600 (CST) From: Chris Dillon <cdillon@inter-linc.net> To: freebsd-fs@FreeBSD.ORG Subject: May have pounced on something weird with ccd and newfs (rather old) Message-ID: <XFMail.980204002044.cdillon@inter-linc.net>
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A short time ago (late November or early December of 1997, about when these
maillists started bouncing mail for people that didn't have valid reverse
lookups) I tried to post a bit about the tests I I did to figure out which ccd
stripe size would probably work best with my equipment. Running 2.2.5-stable,
I set up two new IBM DCAS-34330W's (4.3GB UW-SCSI) on a Tekram DC-390F and tried
setting various stripe sizes with ccd and running bonnie on the resulting
filesystems. I did something like this:
ccdconfig -c ccd0 $BLOCKSIZE 0 /dev/sd0s1g /dev/sd1s1g
newfs -b 8192 -f 1024 ccd0c
mount /dev/ccd0c /mnt
bonnie -d /mnt -s 100 -m "I=$BLOCKSIZE" | grep "I=" >> ~/ccdtest.txt
umount -f /dev/ccd0c (only did -f since weirdly enough, it would fail sometimes)
ccdconfig -u ccd0
BLOCKSIZE varied from 0 to 8192, in powers of two (0, 16, 32, 64, etc.).
Here is the resulting output of the above.
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
std 100 3462 97.9 7636 40.8 2976 28.6 3732 98.6 7942 32.3 153.9 7.2
I=0 100 3422 98.0 7311 37.1 2905 28.0 3707 98.5 7404 29.8 156.8 7.5
I=16 100 3319 96.1 12043 81.3 4515 45.4 3626 97.3 12683 66.4 167.3 8.2
I=32 100 3418 97.2 13433 87.8 4747 46.1 3671 98.3 14597 77.5 164.5 8.1
I=64 100 3413 97.0 13986 89.9 4844 47.2 3700 98.9 14703 74.8 166.9 8.2
I=128 newfs -b 8192 -f 1024 fails with "write error: 2047871
wtfs: invalid argument".
I=256 100 3433 97.3 12782 92.2 4912 52.7 3718 98.9 13539 88.9 165.9 9.3
I=512 100 3474 98.1 12391 86.7 6107 66.6 3746 98.8 12306 75.7 166.6 9.3
I=1024 100 3473 98.0 12403 91.1 4449 49.5 3735 98.5 9870 57.7 170.4 9.6
I=2048 100 3453 98.0 11876 88.2 3493 39.1 3752 98.8 8397 47.0 168.9 9.5
I=4096 100 3449 98.1 11851 84.0 3217 35.6 3708 98.2 7922 44.2 169.3 9.5
I=8192 100 3464 97.8 12011 87.9 3116 32.8 3745 99.0 7652 42.4 174.8 9.9
"std" is the output when NOT using ccd (i.e., a regular disk). With a ccd
stripe size of 128, newfs refused to create a filesystem with the error you see
above. (I decided on using the 64 block stripe ultimately, by the way.)
Is this a known anomaly, or did I stumble onto some underlying problem? If
this is common knowledge, please enlighten me. :-)
This also seemed like the appropriate maillist to post this to (I'm on just
about ALL of them), but if not, I'll move it elsewhere.
--- Chris Dillon
--- cdillon@inter-linc.net
--- Powered by FreeBSD, the best operating system on the planet
for Intel x86 based computers (and soon Sparcs).
---- (http://www.freebsd.org)
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