All,
I am attempting to help tune a Sun for better performance (mainly for SAS 9.1), and have found indicators pointing to poor I/O utilization. I have run iostat -cx, and found one device in particular where the %w is in the 90's during processing. I have a feeling that this is where the SAS... (3 Replies)
I'm search for a disk exerciser / load tool like iometer, iozone, diskx for IBM AIX 5.2 and 5.3
Because of a very bad disk performance on several AIX systems, I need to have a tool which is able to generate a disk load on my local and SAN disks.
Does somebody knows a kind of tool which is... (5 Replies)
Friends.
I have to compare iostat -x output with a tool on solaris. Now there is column called wait in the output field which is showing zero. Now, in order to create some load on my system this is what i am doing
I am creating a file using dd command , the size of which is... (5 Replies)
Hello,
On Solaris 10, iostat -E gives me the following results:
sd1 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: FUJITSU Product: MAY2073RCSUN72G Revision: 0501 Serial No: 0708S08M2L
Size: 73.40GB <73400057856 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0... (1 Reply)
Hi, can anyone please suggest a tool to dump i/o packets just like tcpdump does for network traffic. Basically I have a complex dataflow that needs to be optimized and I want to see how packets go to/from disk - what goes randomly and sequentially.
Thanks (8 Replies)
A find for the "iostat" command on a redhat 5 update 4 comes back with no results.
Any separate rpm needs to be installed to get the binary for this ?
Thanks in advance. (1 Reply)
Writing a Tool to simulate non-sequential disk I/O (simulate db file sequential read) in C POSIX
I have over the years come across the same issue a couple of times, and it normally is that the read speed on SAN is absolutely atrocious when doing non-sequential I/O to the disks. Problem being of... (7 Replies)
Hello everyone,
Can you please explain me what kind of information do IOSTAT show ?
iostat -xnz 3 show me those informations:
The I/O of the c0t0d0 disk is normal ?
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
0.0 ... (3 Replies)
Hello, I support Oracle 11g on AIX 7.1.
Using the command
$iostat -D hdisk2 hdisk4 hdisk5 5
I get the following output:
hdisk5 xfer: %tm_act bps tps bread bwrtn
44.0 1.4M 178.2 1.4M 14.7K
read: ... (3 Replies)
Hi Everyone,
I try to calculate the total hard disk space of a solaris machine using iostat -En command. Iterating the output and summing up all the number present near the Size: will give the exact size of the harddisk. But it is not working for a machine.
This command works in many flavors... (2 Replies)
Discussion started by: prasankn
2 Replies
LEARN ABOUT V7
iostat
IOSTAT(1M)IOSTAT(1M)NAME
iostat - report I/O statistics
SYNOPSIS
iostat [ option ] ... [ interval [ count ] ]
DESCRIPTION
Iostat delves into the system and reports certain statistics kept about input-output activity. Information is kept about up to three dif-
ferent disks (RF, RK, RP) and about typewriters. For each disk, IO completions and number of words transferred are counted; for typewrit-
ers collectively, the number of input and output characters are counted. Also, each sixtieth of a second, the state of each disk is exam-
ined and a tally is made if the disk is active. The tally goes into one of four categories, depending on whether the system is executing
in user mode, in `nice' (background) user mode, in system mode, or idle. From all these numbers and from the known transfer rates of the
devices it is possible to determine information such as the degree of IO overlap and average seek times for each device.
The optional interval argument causes iostat to report once each interval seconds. The first report is for all time since a reboot and
each subsequent report is for the last interval only.
The optional count argument restricts the number of reports.
With no option argument iostat reports for each disk the number of transfers per minute, the milliseconds per average seek, and the mil-
liseconds per data transfer exclusive of seek time. It also gives the percentage of time the system has spend in each of the four cate-
gories mentioned above.
The following options are available:
-t Report the number of characters of terminal IO per second as well.
-i Report the percentage of time spend in each of the four categories mentioned above, the percentage of time each disk was active
(seeking or transferring), the percentage of time any disk was active, and the percentage of time spent in `IO wait:' idle, but with
a disk active.
-s Report the raw timing information: 32 numbers indicating the percentage of time spent in each of the possible configurations of 4
system states and 8 IO states (3 disks each active or not).
-b Report on the usage of IO buffers.
FILES
/dev/mem, /unix
IOSTAT(1M)
06-29-2010
