Date: Tue, 08 Nov 2005 10:00:11 -0800 From: Drew Tomlinson <drew@mykitchentable.net> To: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Disk Access Seems Slow in 5.4 Message-ID: <4370E7AB.5000401@mykitchentable.net>
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I have two boxes running FBSD. One is an old AMD 350 mhz machine with
just 128 MB of RAM and a 4 GB IDE drive that's attached to a 33mhz
controller. The other is a dual Pentium 600 machine with 768 MB RAM and
two 9 GB SCSI drives.
Ever since I upgraded the dual Pentium from 4.11 to 5.4, disk access
seems slower. I can't know for sure because I never did any
benchmarking before. I used vinum striping in 4.x but moved to gstripe
in 5.4. I notice it most when using an IMAP client to connect to
Courier on this 5.4 machine. So maybe it's just slow with small files?
Here's my 'gstripe list' output so you can see how the stripe set is built:
--- BEGIN ---
blacklamb# gstripe list
Geom name: data
State: UP
Status: Total=2, Online=2
Type: AUTOMATIC
Stripesize: 131072
ID: 1477809630
Providers:
1. Name: stripe/data
Mediasize: 17160732672 (16G)
Sectorsize: 512
Mode: r1w1e0
Consumers:
1. Name: da1s1d
Mediasize: 8580481024 (8.0G)
Sectorsize: 512
Mode: r1w1e1
Number: 1
2. Name: da0s1d
Mediasize: 8580481024 (8.0G)
Sectorsize: 512
Mode: r1w1e1
Number: 0
--- END ---
I really don't know what to check or how to go about checking it. I
Googled and found that bonnie++ seems to be popular. Another is
postmark. I installed these tools and ran them both on my 5.4 server
with the SCSI drives and the 4.11 server with the slow 33mhz IDE drive
in it. Using default settings, postmark shows the 5.4 box about 2 1/2
times slower than the 4.11 box.
--- BEGIN 5.4 Box ---
Creating files...Done
Performing transactions..........Done
Deleting files...Done
Time:
24 seconds total
9 seconds of transactions (55 per second)
Files:
764 created (31 per second)
Creation alone: 500 files (100 per second)
Mixed with transactions: 264 files (29 per second)
243 read (27 per second)
257 appended (28 per second)
764 deleted (31 per second)
Deletion alone: 528 files (52 per second)
Mixed with transactions: 236 files (26 per second)
Data:
1.36 megabytes read (58.22 kilobytes per second)
4.45 megabytes written (189.70 kilobytes per second)
--- END 5.4 Box ---
--- BEGIN 4.11 Box ---
pm>run
Creating files...Done
Performing transactions..........Done
Deleting files...Done
Time:
10 seconds total
4 seconds of transactions (125 per second)
Files:
764 created (76 per second)
Creation alone: 500 files (100 per second)
Mixed with transactions: 264 files (66 per second)
243 read (60 per second)
257 appended (64 per second)
764 deleted (76 per second)
Deletion alone: 528 files (528 per second)
Mixed with transactions: 236 files (59 per second)
Data:
1.36 megabytes read (139.72 kilobytes per second)
4.45 megabytes written (455.28 kilobytes per second)
--- END 4.11 Box ---
I also ran bonnie++ on both boxes Here's ouput from the 5.4 box
Version 1.93c ------Sequential Output------ --Sequential Input-
--Random-
Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
blacklamb 300M 39 99 9115 18 8273 20 107 99 112354 99
2306 207
Latency 329ms 129ms 314ms 150ms 1557us
2365ms
Version 1.93c ------Sequential Create------ --------Random
Create--------
blacklamb -Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
16 75 3 19237 99 116 3 75 3 19069 99
185 6
Latency 384ms 212us 260ms 209ms 662us
464ms
And here's from the 4.11 box:
Version 1.93c ------Sequential Output------ --Sequential Input-
--Random-
Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
blacksheep 300M 47 96 4262 8 1954 5 101 96 4442 5
68.2 5
Latency 705ms 532ms 442ms 265ms 291ms
9196ms
Version 1.93c ------Sequential Create------ --------Random
Create--------
blacksheep -Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
16 3806 62 12911 78 9469 91 3644 57 15577 99
2940 29
Latency 342ms 13128us 658us 247ms 644us
714ms
I don't really know what all of this means. However the 4.11 box
finished both tests much faster than the 5.4 box. Thus it seems I have
a drive performance issue. What should I do to improve performance on
the 5.4 box? I'm getting ready to upgrade to 6.0 and see this as an
opportunity to modify the disk parameters if needed.
Thanks,
Drew
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