similar to: iostat results for multi path disks

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, I'm a newbie to tool 'iostat' and I've read the manual for iostat several times. But it doesn't help. I still get confused with the output of 'iostat', the manual seems too abstract, or high-level, for me. Let's post the output first: avg-cpu: %user %nice %sys %idle 5.70 0.00 3.15 91.15 Device: rrqm/s wrqm/s r/s w/s

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

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

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

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

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

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

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)

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

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

I?m looking for advice and considerations on how to optimally setup and deploy an NFS-based home directory server. In particular: (1) how to determine hardware requirements, and (2) how to best setup and configure the server. We actually have a system in place, but the performance is pretty bad---the users often experience a fair amount of lag (1--5 seconds) when doing anything on their home

Hi, folks, I''m attempting to run an e-mail server on Xen. The e-mail system is Novell GroupWise, and it serves about 250 users. The disk volume for the e-mail is on my SAN, and I''ve attached the FC LUN to my Xen host, then used the "phy:/dev..." method to forward the disk through to the domU. I''m running into an issue with high I/O wait on the box (~250%)

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

The minimum is set at 1200Kbits/second. However, in testing, if I set that for a VNIC, the domU gets no traffic at all (maybe the occassional packet). Is the minimum too low? If I set a maximum of 2000Kbits/second, I get this from nicstat (expecting around 250Kbytes/s total: Time Int rKB/s wKB/s rPk/s wPk/s rAvs wAvs %Util Sat 04:35:38 xvm15_0 146.6 5.32 102.0

The minimum is set at 1200Kbits/second. However, in testing, if I set that for a VNIC, the domU gets no traffic at all (maybe the occassional packet). Is the minimum too low? If I set a maximum of 2000Kbits/second, I get this from nicstat (expecting around 250Kbytes/s total: Time Int rKB/s wKB/s rPk/s wPk/s rAvs wAvs %Util Sat 04:35:38 xvm15_0 146.6 5.32 102.0

I?ve posted this on the forums at https://www.centos.org/forums/viewtopic.php?f=47&t=57926&p=244614#p244614 - posting to the list in the hopes of getting more eyeballs on it. We have a cluster of 23 HP DL380p Gen8 hosts running Kafka. Basic specs: 2x E5-2650 128 GB RAM 12 x 4 TB 7200 RPM SATA drives connected to an HP H220 HBA Dual port 10 GB NIC The drives are configured as one large

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

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