03-03-2005
iostat -e / -E output explanation
Hi all, hope you are having a nice day, its nice and warm today in Canberra Australia.
iostat -e / -E reports soft and hard errors. Any idea what these are exactly? All I hear are I/O's failing and needing to retry, but no cause as to why they fail.
My SUN guru tells me its our EMC SAN array generating RSCN's or other fibre channle stuff, and the qlogic card then logs back into the fabric, and during that process some I/O has failed. However the iostat errors come up regardless of the EMC san.
I have searched for and read articles, etc, and really found nothing. however one article said the scsi driver doesn't know the disk RPM speed, another saying that SUN array software needs to be turned off.
We have a history with SUNmc causing SAN disk problems by constantly polling the disk for information (which is why we are upgrading it and have turned it off on some servers).
If you have lots of soft errors, are you likely to get a hard error? When you have lots of hard errors (eg, an internal disk is reporting 2400 hard errors with no corresponsing /var/adm/message entries to do with RSCN, scsi, etc) will you end up with track/cylinder errors?
I guess database/application issues will also cause I/O retries just like tcpip.
The number of network output/inpuit/collisions/queues, also do not relate to the iostat -e output.
Many Thanks
take care all
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plimit(1) User Commands plimit(1)
NAME
plimit - get or set the resource limits of running processes
SYNOPSIS
plimit [-km] pid...
plimit {-cdfnstv} soft,hard... pid...
DESCRIPTION
If one or more of the cdfnstv options is specified, plimit sets the soft (current) limit and/or the hard (maximum) limit of the indicated
resource(s) in the processes identified by the process-ID list, pid. Otherwise plimit reports the resource limits of the processes identi-
fied by the process-ID list, pid.
Only the owner of a process or the super-user is permitted either to get or to set the resource limits of a process. Only the super-user
can increase the hard limit.
OPTIONS
The following options are supported:
-k On output, show file sizes in kilobytes (1024 bytes) rather than in 512-byte blocks.
-m On output, show file and memory sizes in megabytes (1024*1024 bytes).
The remainder of the options are used to change specified resource limits. They each accept an argument of the form:
soft,hard
where soft specifies the soft (current) limit and hard specifies the hard (maximum) limit. If the hard limit is not specified, the comma
may be omitted. If the soft limit is an empty string, only the hard limit is set. Each limit is either the literal string unlimited, or a
number, with an optional scaling factor, as follows:
nk n kilobytes
nm n megabytes (minutes for CPU time)
nh n hours (for CPU time only)
mm:ss minutes and seconds (for CPU time only)
The soft limit cannot exceed the hard limit.
-c soft,hard Set core file size limits (default unit is 512-byte blocks).
-d soft,hard Set data segment (heap) size limits (default unit is kilobytes).
-f soft,hard Set file size limits (default unit is 512-byte blocks).
-n soft,hard Set file descriptor limits (no default unit).
-s soft,hard Set stack segment size limits (default unit is kilobytes).
-t soft,hard Set CPU time limits (default unit is seconds).
-v soft,hard Set virtual memory size limits (default unit is kilobytes).
OPERANDS
The following operands are supported.
pid Process ID list.
EXIT STATUS
plimit returns the exit value zero on success, non-zero on failure (such as no such process, permission denied, or invalid option).
FILES
/proc/pid/* process information and control files
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWesu |
+-----------------------------+-----------------------------+
SEE ALSO
ulimit(1), proc(1), getrlimit(2), setrlimit(2), proc(4), attributes(5),
SunOS 5.10 8 Jun 1998 plimit(1)