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 OSF1
iostat
iostat(1) General Commands Manual iostat(1)NAME
iostat - Reports I/O statistics
SYNOPSIS
iostat [drive...] [interval] [count]
OPERANDS
Forces iostat to display specific drives. If drive is not specified (or the specified drive does not exist on the system or cluster,
iostat displays the first two drives (even if more than two disk drives are configured in the system). Causes iostat to report once each
interval seconds. The first report is for all time since the system was last booted, and each subsequent report is for the last interval
only.The value must not be 0. Specifies the number of reports. For example, iostat 1 10 would produce 10 reports at 1-second intervals.
You cannot specify count without interval because the first numeric argument to iostat is assumed to be interval.
DESCRIPTION
The iostat command reports the following information: For terminals (collectively), the number of characters read and written per second.
For each disk, the number of transfers per second and bytes transferred per second (in kilobytes). For the system, the percentage of time
the system has spent in user mode, in user mode running low priority (nice) processes, in system mode, and idling.
To compute this information, iostat counts data transfer completions, the number of words transferred for each disk, and the collective
number of input and output characters for terminals. Also, each sixtieth of a second, iostat examines the state of each disk and makes a
tally if the disk is active.
When you issue an iostat command on a cluster member, it displays statistics only for those disks that are local to the member and that
member's usage of those shared disks that it has mounted. It displays 0 for other disks in the cluster (those it doesn't have mounted),
regardless of whether they are on the shared bus or are local to some other member.
EXAMPLES
The output from this example displays cpu, terminal, and disk statistics for the first two disks on the system providing 5 reports at 1
second intervals:
# iostat 1 5
tty floppy1 dsk9 cpu
tin tout bps tps bps tps us ni sy id
0 3 0 0 0 0 1 0 4 95
4 58 0 0 0 0 1 0 2 97
1 53 0 0 0 0 0 0 2 98
5 59 0 0 0 0 1 0 1 98
6 60 0 0 0 0 1 0 2 97
The second example specifies device names in the command:
# iostat dsk2 dsk3 cdrom2
tty dsk2 cdrom2 dsk3 cpu
tin tout bps tps bps tps bps tps us ni sy id
0 13 11 5 5 2 2427 1213 0 1 1 98
SEE ALSO Commands:vmstat(1)iostat(1)