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Questions tagged [iostat]

iostat displays the current CPU load average and disk I/O information.

iostat (input/output statistics) is a computer system monitor tool used to collect and show operating system storage input and output statistics.

The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates. The iostat command generates reports that can be used to change system configuration to better balance the input/output load between physical disks.

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What Process is using all of my disk IO

If I use "top" I can see what CPU is busy and what process is using all of my CPU. If I use "iostat -x" I can see what drive is busy. But how do I see what process is using all of the drive's throughput?
Party King
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Tool which shows me which files are written in Linux?

I found in IOStat, that some part of my application is writing extensively, but I don't know which process it is and what files it is writing to. In Vista there is a tool fo that which shows the files that have been active in the last 30 Seconds. Is…
smint
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Map sd?/sdd? names to Solaris disk names?

Some commands in Solaris (such as iostat) report disk related information using disk names such as sd0 or sdd2. Is there a consistent way to map these names back to the standard /dev/dsk/c?t?d?s? disk names in Solaris? Edit: As Amit points out,…
Erlend Leganger
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How to interpret iostat?

I track a lot of parameters on my Server and the only thing I can't realy put in perspective is the IOstat. It is a MySQL Server, is this a good result, or should I worry? root:/var/lib/mysql# iostat -xc Linux 2.6.28-11-server () 07/25/2009 …
smint
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Postgres create/restore taking lot of time on amazon ec2

I have a amazon ec2 instance(SAY S1)(4core-7GB memory) using Ubuntu 12.04, which is running my web app with postgresql 9.1. All the postgres data is stored on to a different ssd volume(not root) of 100 GB. (Write now its currently 26% full only ) .…
Ankit Kulkarni
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Why read per second (r/s) in linux command (iostat) all the time is zero?

I run a java code that produces a lot of read and write from/to a text file. The program source is very simple and in a loop I write 2000 lines in a test file and then I read them again just to generate a lot of read and write to the disk. But when…
Sepehr Samini
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iotop does not show any disk read statistics

I am running a test to check disk read statistics. Here is the code for the same: #include #include #include int main(int argc, char* argv) { int count=1000, size; char block[4096]="0"; int fd =…
Saunved Mutalik
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Tuning Nginx/CentOS for server lots of static content

I have a linux machine 64bit (centos5.5), 2.83GHz Q9550, 6gb ram and a single SATA 500gb drive. From this machine I only serve thumbnails, most around 10kb in size and at this point there are about 7 million thumbnails on the server. I have them…
Mr.Boon
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how to awk the command IOSTAT -DlR 1 2

input: #iostat -DlR 1 2 Output: root@myserver #iostat -DlR 1 2 System configuration: lcpu=20 drives=2 paths=16 vdisks=0 Disks: xfers read write …
Danny Perry
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Using memory mapped files with docker and alpine

We have an java application that recently has been ported to docker. This application uses memory mapped files. We have observed a huge performance degradation when doing this change and we are trying to diagnose exactly why this happened. Our…
hveiga
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linux IOSTAT double counting AIO write operations?

As part of debugging an IO generator, I've run across an odd set of results under RH 6.4 running on x64 hardware (validated on multiple systems): -- The application uses linux async IO (i.e., non-posix) to access raw disk partitions (/dev/sdb1,…
Jack Stephens
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how to make iostat behave like top

iostat -xzN 5 | grep "^vg\|^Dev" produces output like: Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util vg01-root 0.00 0.00 0.00 0.20 0.00 1.60 8.00 0.00 …
Dokbua
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device naming zfs vs smartctl vs iostat

I'm working on gathering performance metric data from a SAN (5.11 omnios-7648372 ). we use dataon JBOD. a snip of Output of zdb -C mypoolname : children[0]: type: 'disk' id: 0 guid: 7701924650939559899 path: '/dev/dsk/c1t0d0s0' …
Bino Oetomo
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how to query sar(sysstat) for more than one day data points

I don't see 'sar' command accepts date-and-time as starttime(-s) or endtime(-e) than just time. So, how to query 'sar' for more than one day's data points by passing older datetime values(-f not going to help here). The output of the 'sar' command…
Murali Mopuru
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Why writes with O_DIRECT and O_SYNC still causing io merge?

everyone Recently, I did some test with fio to test my disk performance. I configured fio to use direct io and O_SYNC, and following is my configuration [global] invalidate=0 #…
Rainman1985
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