Date: Wed, 21 Mar 2007 14:54:20 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-performance@FreeBSD.ORG, "roma.a.g" <roma.a.g@gmail.com> Subject: Re: Slow on heavy I/O operations. Message-ID: <200703211354.l2LDsKnV080911@lurza.secnetix.de> In-Reply-To: <1036039198.20070321153412@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Roman Gorohov. <roma.a.g@gmail.com> wrote:
> Hello list.
> There is a server with FreeBSD FreeBSD 4.11-STABLE(can't upgrade fornow) on HP ProLiant DL140.
> Disk system: <SEAGATE ST373207LC 0005> at scbus0 target 0 lun0(pass0,da0) on a ASC-29320A.
> If I do:
> [idle@hst ~]#dd if=/dev/zero of=bigfile bs=64k count=5000
> 5000+0 records in
> 5000+0 records out
> 327680000 bytes transferred in 37.515699 secs (8734477 bytes/sec)
> All is hung while dd working.
>
> Its look like that:
> [idle@hst ~]#systat -v
> skip...
> Disks da0 pass0 pass1 md0
> KB/t 20.33 0.00 0.00 0.00
> tps 812 0 0 0
> MB/s 16.11 0.00 0.00 0.00
> % busy 100 0 0 0
> skip...
>
> [idle@hst ~]#vmstat -w 5
> procs memory page disks faults cpu
> r b w avm fre flt re pi po fr sr da0 md0 in sy cs us sy id
> 1 0 0 1996756 54208 42 23 25 7 39 336 0 0 531 638 404 21 5 74
> 1 6 0 2011488 13272 571 0 0 1 2506 8 129 0 1356 2125 159 3 4 93
> 4 27 0 2022852 4228 267 0 0 1 1657 4 272 0 1450 784 96 1 3 96
> 1 10 0 2027492 40220 449 5 0 12 3257 9384 574 0 1773 4366 189 8 7 85
> 1 10 0 2035064 25604 746 2 1 7 2965 4466 157 0 1380 4486 184 8 7 85
> 0 11 0 2030860 4228 515 2 1 3 2098 31 214 0 1412 3077 149 16 5 79
> 3 14 0 2042792 10004 1014 4 1 5 2787 4432 267 0 1440 1735 118 2 4 94
> 2 16 0 2062664 4228 301 0 1 2 2843 27 564 0 1759 1250 107 5 4 91
>
> [idle@hst ~]#iostat -w 5
> tty da0 pass0 pass1 cpu
> tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
> 0 25 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 21 0 4 0 74
> 1 109 62.56 242 14.81 0.00 0 0.00 0.00 0 0.00 7 0 9 0 83
> 0 101 18.29 433 7.73 0.00 0 0.00 0.00 0 0.00 2 0 2 0 95
> 0 76 26.45 281 7.25 0.00 0 0.00 0.00 0 0.00 3 0 4 0 93
> 0 94 15.99 357 5.57 0.00 0 0.00 0.00 0 0.00 2 0 2 0 96
> 0 15 16.04 667 10.45 0.00 0 0.00 0.00 0 0.00 0 0 3 1 96
> 0 93 15.99 558 8.71 0.00 0 0.00 0.00 0 0.00 0 0 2 1 97
> 0 80 16.16 252 3.98 0.00 0 0.00 0.00 0 0.00 0 0 1 0 98
> 0 117 23.44 240 5.49 0.00 0 0.00 0.00 0 0.00 9 0 6 0 85
>
> Why this happen?
The numbers from your vmstat output indicate that your
machine is paging ("swapping"), i.e. it's running out
or RAM.
Of course, such paging activity competes with other I/O
operations in the system, which explains the symptoms
that you're seeing.
> What should I do?
Either add more RAM, or reduce the memory requirements
of your applications, if possible.
Another work-around wold be to add a second disk and use
it exclusively for swap. That way it won't compete with
I/O operations on yoru data disk. The paging will still
slow down your machine, though, therefore you should
really try to add more RAM.
Best regards
Oliver
--
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart
FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd
"What is this talk of 'release'? We do not make software 'releases'.
Our software 'escapes', leaving a bloody trail of designers and quality
assurance people in its wake."
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200703211354.l2LDsKnV080911>