similar to: How to interpret the output of 'iostat -x /dev/sdb1 20 100' ??

Hi All, I have a client trying to us a Promise Tech iSCSI array to share 2.8TB via SAMBA. I have CentOS 4.2 with all updates installed on an IBM server. The installation and setup was pretty straightforward. The Promise box is using Gigabit Ethernet, and is the only device on that net (I think they are using a cross-over cable - I didn't set up the hardware). We're experiencing

I did some additional testing - I stopped Kafka on the host, and kicked off a disk check, and it ran at the expected speed overnight. I started kafka this morning, and the raid check's speed immediately dropped down to ~2000K/Sec. I then enabled the write-back cache on the drives (hdparm -W1 /dev/sd*). The raid check is now running between 100000K/Sec and 200000K/Sec, and has been for several

All of our Kafka clusters are fairly write-heavy. The cluster in question is our second-heaviest ? we haven?t yet upgraded the heaviest, due to the issues we?ve been experiencing in this one. Here is an iostat example from a host within the same cluster, but without the RAID check running: [root at r2k1 ~] # iostat -xdmc 1 10 Linux 3.10.0-327.13.1.el7.x86_64 (r2k1) 05/27/16 _x86_64_ (32 CPU)

Here is a sample of running iostat on a server that has a LUN from a SAN with multiple paths. I am specifying a device list that just grabs the bits related to the multi path device: $ iostat -dxkt 1 2 sdf sdg sdh sdi dm-7 dm-8 dm-9 Linux 2.6.18-371.8.1.el5 (db21b.den.sans.org) 06/20/2014 Time: 02:30:23 PM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await

We are struggling with a strange problem. When we have some VMWare clients running (mostly MS windows clients), than the IO-write performance on the host becomes very bad. The guest os's do not do anything, just having them started, sitting at the login prompt, is enough to trigger the problem. The host has plenty of 4G of RAM, and all clients fit easily into the space. The disksystem is a

Hi, I have high IO-Wait on the ods (ceph), the osd are running a v3.1-rc9 kernel. I also experience high IO-rates, around 500IO/s reported via iostat. Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sda 0.00 0.00 0.00 6.80 0.00 62.40 18.35 0.04 5.29 0.00 5.29 5.29 3.60 sdb

Hi all, I just installed centos 5.4 xen-kernel on intel core i5 machine as dom0. After some hours of syncing a raid10 array (8 sata disk) I noticed a steadily increasing loadavg. I think without reasonable i/o wait or cpu utilization the loadavg on this system should be very lower. If this loadavg is normal I would be greatful if somone could explain why. The screenshots below show that there is

I'm having load problems on a server. The bottleneck appears to be disk IO. iostat would show ~100, under %util, during peak usage. i'm running things like clam antivirus, pop, exim, apache, mysql on the server. is there a way to check which process and which file is taking up disk IO? or see what is being written to the disk? i'm very puzzled as the amount of writes is 10 times

Hi. I'm testing a centos 5.4 xen PV guest on top of a centos 5.4 host. for some reason, the disk performance from the guest is awful. when I do an import , the io is fine for a while then climbs to 100% and stays there most of the time. at first I tougth it was because I was using file-backed disks, so deleted those and changed to LVM, but the situation did't improve. Here's an

I just installed CentOS 5.4 64 bit release on a 1.9ghz CPU with 8gB of RAM. It has 2 Western Digital 1.5TB SATA2 drives in RAID1. [root at server ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/md2 1.4T 1.4G 1.3T 1% / /dev/md0 99M 19M 76M 20% /boot tmpfs 4.0G 0 4.0G 0% /dev/shm [root at server ~]# Its barebones

We are currently experiencing performance issue with our Dovecot system which we believe is caused by excessive writes to the dovecot files. The confusing thing is that we are seeing more writes than reads on our Dovecot volume when you would assume that most of the IO should be reads from customers checking their mail. We're seeing reads vs. writes similar to the following: # iostat -d 5 -x

Hello, I'm writing from the otherside of the world from where my systems are, so details are coming in slow. We have a 6TB OCFS2 volume across 20 or so nodes all running OEL5.4 running ocfs2-1.4.4. The system has worked fairly well for the last 6-8 months. Something has happened over the last few weeks which has driven write performance nearly to a halt. I'm not sure how to proceed, and

Hi, I'm running a CentOS 4. server and I sometimes face a weird problem. It is a weird performance problem, and here is how I discovered it. This server runs OpenVZ virtual machines, and one of them is an asterisk server for my personal use. The first symptom of the problem is that the voice quality became flaky. So I logged on the server to see what could be eating cpu cycles, when I

we're having a weird disk I/O problem on a 5.4 server connected to an external SAS storage with an LSI logic megaraid sas 1078. The server is used as a samba file server. Every time we try to copy some large file to the storage-based file system, the disk utilization see-saws up to 100% to several seconds of inactivity, to climb up again to 100% and so forth. Here are a snip from the iostat

Am 2015-09-17 09:29, schrieb Pasi K?rkk?inen: > > Are you using nfs over UDP or TCP ? > TCP, but Network cant be the bottleneck, have tested it with iperf between bare metal/domU's and the nfs domU and it was perfectly fast... > > I don't think. > > > If you used NFS over UDP, try running it over TCP. no I use it over TCP... > > What does

Op 29-01-15 om 21:21 schreef Gordon Messmer: > > I haven't seen delays anywhere near that long before, even with heavy swapping. But I guess I'd look at that sort of thing first. > > Run "iostat -x 2" and see if your disks are being fully utilized during the pauses. Run "top" and see if there's anything useful there. Check swap use with

Hi, I am currently running a 10 Node OCFS2 Cluster (version 1.3.9-0ubuntu1) on Ubuntu Server 8.04 x86_64. Linux n1 2.6.24-24-server #1 SMP Tue Jul 7 19:39:36 UTC 2009 x86_64 GNU/Linux The Cluster is connected to a 1Tera iSCSI Device presented by an IBM 3300 Storage System, running over a 1Gig Network. Mounted on all nodes: /dev/sdc1 on /cfs1 type ocfs2

Adding Paolo and Miroslav. On Sat, Apr 8, 2017 at 4:49 PM, Richard Landsman - Rimote <richard at rimote.nl > wrote: > Hello, > > I would really appreciate some help/guidance with this problem. First of > all sorry for the long message. I would file a bug, but do not know if it > is my fault, dm-cache, qemu or (probably) a combination of both. And i can > imagine some of

Hi, i have a vm which has a poor performance. E.g. top needs seconds to refresh its output on the console. Same with netstat. The guest is hosting a MySQL DB with a webfrontend, its response is poor too. I'm looking for the culprit. Following top in the guest i get these hints: Memory is free enough, system is not swapping. System has 8GB RAM and two cpu's. Cpu 0 is struggling with a

Hello everyone, Anybody had the chance to test out this setup and reproduce the problem? I assumed it would be something that's used often these days and a solution would benefit a lot of users. If can be of any assistance please contact me. -- Met vriendelijke groet, Richard Landsman http://rimote.nl T: +31 (0)50 - 763 04 07 (ma-vr 9:00 tot 18:00) 24/7 bij storingen: +31 (0)6 - 4388