0
votes
0answers
72 views

confused by iostat reporting striped mdadm more tps than aggregate volumes

I've got an mdadm striped device (/dev/md0) from /dev/sdm{1..4}. Here is an output of iostat 30 and then mdadm --detail on the mdadm device # iostat 30 Linux 2.6.32-309-ec2 (ip-xx-xx-xx-xx) ...
1
vote
1answer
117 views

Strange iostat numbers

I'm experiencing unusual load issue on one of our VM which is on SAN storage. As a general practice I ran iostat on the server got very strange numbers. avg-cpu: %user %nice %system %iowait ...
1
vote
0answers
307 views

MySql/RedHat, High I/O Wait … for a few hours… then disappears

I've got a RH server as a VMWare instance logging GPS fixes 24x7. The transaction volume hasn't changed over the months (in fact I am pruning the transaction table more aggressively now) with only ...
-1
votes
0answers
54 views

Is there a way to find out why IO is so high? [duplicate]

Possible Duplicate: Detecting Disk Writes Linux Why my server has high load despite mere 1.5% CPU usage My server has high load despite low CPU usage. I did root@host [/var/log]# ...
-1
votes
3answers
2k views

iostat shows 100% utilization - what can be done to improve performance?

I have dedicated web server with CentOS. Recently, I get very high server load, probably caused due to IO bottleneck. iostat -mx 3 shows: avg-cpu: %user %nice %system %iowait %steal %idle ...
2
votes
2answers
140 views

Do we need to perform disk checking periodically on Linux

Do we need to perform periodic disk checking,for bad blocks and bad sectors?. Our servers havent been restarted for last 4 months,also no disk checking have been performed on any disks. Can that can ...
1
vote
2answers
870 views

How iostat figures out to take CPU idle time to consider as %idle or %iowait?

I was going through iostat man page. According to it, %iowait Show the percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request. %idle ...
0
votes
1answer
74 views

how can I tell if there is a cpu trashing on my linux machine

I want to write a script that will kill my processes when my machine is doing "too much" swapping of process memory from disk to memory. What is the best way to determine that? I saw top has %wa and ...
0
votes
2answers
879 views

tracking down what files are causing io activity in iostat

Using iostat -Nkx 1 I can see that I am getting regular IO on a volume group. What I'm trying to do is find a way to link that IO to a file/pipe/whatever to see what process is creating this IO and ...
4
votes
3answers
836 views

Linux utility to record IO statistics (random/sequential, block sizes, read/write ratio)

As part of provisioning our new server (see other SF) I'd like to find out the following: ratio of random to sequential reads & writes amount of data read & written at a time (pref in ...
2
votes
4answers
890 views

very specific iostat output needed in realtime

Is there anyway to get the output of iostat -m and add only the column await from the extended output in realtime? I know this question sounds nutso but I need to be able to get all those column in ...
1
vote
3answers
1k views

No apparent reason for high load average

We have several web servers running on Amazon (ec2) c1.xlarge, over Amazon AMI. The servers are duplicates of each other, running the exact same hardware and software. Each server spec is: 7 GB of ...
0
votes
0answers
184 views

“iostat” command different in two equal machines

We have several machines on Amazon (ec2) of the type c1.xlarge with 8 cpus, running the Amazon AMI. Details on the machine: 7 GB of memory 20 EC2 Compute Units (8 virtual cores with 2.5 EC2 Compute ...
2
votes
1answer
285 views

RAID iostat showing 0.00 for wait's and %util

I have a EC2 server running ubuntu 11.10 with 6 raid devices, 5 with 8 EBS drives each as part of a RAID 10 setup, the other one with 4 EBS drives as part of a RAID 0 setup. I am finding that even ...
0
votes
1answer
334 views

iostat: See current usage rather than average

I need to log disk statistics (MB/read, MB/write) of block devices. As I understand, iostat shows an average value. This is not exactly what I want when I'm about to monitor a server. Is there a way ...
0
votes
1answer
604 views

IO utilization percent of 4920.45% - iostat -x , What's wrong?

I have seen wrong percent use of a disk IO some times on servers that have been a long time without reboot. By any means this server has significant IO. Tonight it'll be rebooted and I'm sure ...
1
vote
1answer
1k views

iostat how do I set up a logging

Hi there I am pretty newbie in servers, would appreciate your help. How do I set up an iostat logging? as my Disk IO spikes strange at some random time to very high levels. Thanks.
2
votes
4answers
1k views

high iostat load on linux

atop: DSK | cciss/c0d0 | busy 87% | read 24193e4 | write 4076e4 | KiB/r 26 | KiB/w 77 | MBr/s 7.61 | MBw/s 3.78 | avq 6.07 | avio 2.49 ms | iostat Device: tps ...
6
votes
2answers
5k views

can someone explain IOSTAT ouput?

i'am having IBM server with Redhat 5 ElsmP connected to the IBM Storage over iSCSI (in sdb ) can someone explain this output from iostat command avg-cpu: %user %nice %system %iowait %steal ...
1
vote
3answers
7k views

Trouble interpreting iostat's tps measure

Prelude: I dumped a 5.2 GB database using the mysqldump command. I did this on an underpowered virtual server with only 512 MB of memory. It took about an hour. I'm now reloading that database on my ...
7
votes
3answers
12k views

How can I map iostat device names to LVM /dev/mapper/XXX names?

mount shows mount devices like: /dev/mapper/VolGroup01-LogVol00 on /var type ext3 (rw) or /dev/mapper/VolGrp_backups-backups on /mnt/backups type ext3 (rw) but iostat uses dm- notation. like ...