search for: iowait

Hi. I entered one of our domU tonight and see following problem: # iowait -k 5 avg-cpu: %user %nice %system %iowait %steal %idle 0.00 0.00 0.00 100.00 0.00 0.00 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda1 0.00 0.00 0.00 0 0 sda2 0.00 0.00...

...ely each checkpointing and when its reach 0% of idle cpu the local backing device will freeze and damage the replication. Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn drbd1 0.00 0.00 0.00 0 0 avg-cpu: %user %nice %system %iowait %steal %idle 1.52 0.00 6.09 0.00 0.00 92.39 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn drbd1 0.00 0.00 0.00 0 0 avg-cpu: %user %nice %system %iowait %steal %idle 41.24 0.00 1...

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

Hello. We have a number of Xen 3.4.2. boxes which have constant iowaits at around 10% with spikes up to 100% when accessing data over NFS. We have been unable to nail down the issue. Any advice? System info: release : 2.6.18-194.3.1.el5xen version : #1 SMP Thu May 13 13:49:53 EDT 2010 machine : x86_64 nr_cpus...

...o 2 CPUs and 2GB of RAM with no ballooning, and has 2GB of partition-based swap. When creating a new domU on any of the Xen servers, just after the completion of the operating system kickstart install as the new domU completes its shutdown process, the dom0 will begin experiencing high load and an iowait that consumes 100% of one of the CPUs. This will last for several minutes (10-15 generally), and the shutdown of the new domU will usually hang during this time (xm console will not exit, and the domain will continue running until the iowait drops). No swap space will be consumed by the dom0 OS,...

...otal, 25106412 free, 5932244 used, 1567428 buff/cache KiB Swap: 16449532 total, 16449532 free, 0 used. 26282624 avail Mem **iostat** [root at correo ~]# iostat -y 5 Linux 3.10.0-1062.12.1.el7.x86_64 (correo.binal.ac.pa) 07/03/2020 _x86_64_ (4 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 0.05 0.00 0.05 0.05 0.00 99.85 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda 0.00 0.00 0.00 0 0 dm-0 0.00 0.00 0.00 0 0 dm-1...

...ich is acceptable. Reads are in the 8MB/s range which is appalingly slow. Using linux smbclient and windows XP clients I can read at 25+MB/s. I've enabled vfs objects = readahead to get better performance in vista. The biggest difference I notice between vista and other clients is that the %iowait is MUCH higher than with the other clients. Logs show the readahead module being loaded but I have no idea if it is actually doing anything. [2007/10/18 08:24:48, 2] lib/module.c:do_smb_load_module(64) Module '/usr/lib/samba/vfs/readahead.so' loaded Server Config: CPU: Amd Athlon 260...

...t, 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) avg-cpu: %user %nice %system %iowait %steal %idle 8.87 0.02 1.28 0.21 0.00 89.62 Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sdd 0.02 0.55 0.15 27.06 0.03 11.40 859.89 1.02 37.40 36.13 37...

...een 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) > >avg-cpu: %user %nice %system %iowait %steal %idle > 8.87 0.02 1.28 0.21 0.00 89.62 > >Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util >sdd 0.02 0.55 0.15 27.06 0.03 11.40 859.89 1.02 37...

Hello, We have a 5 node OCFS2 volume backed by a Sun (Oracle) StorageTek 2540. Each system is running OEL5.4 and OCFS2 1.4.2, using device-mapper-multipath to load balance over 2 active paths. We are using the default multipath configuration for our SAN. We are observing iowait time between 60% - 90%, sustaining at over 80% as I'm writing this, driving load averages to >25 during an rsync over ssh session. We are copying 200gig via a gigabit ethernet switch, so at most doing 50-60MB/s. The volume we are pushing to is a RAID 5 device backed by 5 7200rpm SATA drives....

Folks, At what point in iowait should I start to worry about having a bottleneck, or is this something that can't be answerd with a single integer? According to sar, after my last reboot to turn off hyperthreading as a test, at one time, I see 4.9% iowait, but then one minute later, it droped back to 0.01%, and rarely e...

On 2016-05-25 19:13, Kelly Lesperance wrote: > Hdparm didn?t get far: > > [root at r1k1 ~] # hdparm -tT /dev/sda > > /dev/sda: > Timing cached reads: Alarm clock > [root at r1k1 ~] # Hi Kelly, Try running 'iostat -xdmc 1'. Look for a single drive that has substantially greater await than ~10msec. If all the drives except one are taking 6-8msec, but one is very

...re at the defaults: dev.raid.speed_limit_max = 200000 dev.raid.speed_limit_min = 1000 Here's 10 seconds of iostat output, which illustrates the issue: [root at r1k1log] # iostat 1 10 Linux 3.10.0-327.18.2.el7.x86_64 (r1k1) ? ?05/24/16 ? ?_x86_64_? ?(32 CPU) avg-cpu:? %user? ?%nice %system %iowait? %steal? ?%idle ? ? ? ? ? ?8.80? ? 0.06? ? 1.89? ?14.79? ? 0.00? ?74.46 Device:? ? ? ? ? ? tps? ? kB_read/s? ? kB_wrtn/s? ? kB_read? ? kB_wrtn sda? ? ? ? ? ? ? 52.59? ? ? 2033.16? ? ?10682.78 1210398902 6359779847 sdb? ? ? ? ? ? ? 52.46? ? ? 2031.25? ? ?10682.78 1209265338 6359779847 sdc? ? ? ? ?...

...16449532 total, 16449532 free, 0 used. 26282624 >avail Mem >> >> **iostat** >> [root at correo ~]# iostat -y 5 >> Linux 3.10.0-1062.12.1.el7.x86_64 (correo.binal.ac.pa) 07/03/2020 >> _x86_64_ (4 CPU) >> >> avg-cpu: %user %nice %system %iowait %steal %idle >> 0.05 0.00 0.05 0.05 0.00 99.85 >> >> Device: tps kB_read/s kB_wrtn/s kB_read >kB_wrtn >> sda 0.00 0.00 0.00 0 >0 >> dm-0 0.00 0...

...pect *some* performance impact of running a read-intensive process like a RAID check at the same time you're running a write-intensive process. Do the same write-heavy processes run on the other clusters, where you aren't seeing performance issues? > avg-cpu: %user %nice %system %iowait %steal %idle > 9.24 0.00 1.32 20.02 0.00 69.42 > > Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn > sda 50.00 512.00 20408.00 512 20408 > sdb 50.00 512.00 20408.00 512...

Just came in from Bugzilla ... Subject: [Bug 121434] Extremely high iowait with 3Ware array and moderate disk activity https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=121434 ------- Additional Comments From thomas.oulevey at elonex.ch 2005-07-29 08:55 EST ------- Hello, About the Linux 2.4 driver, we realized that we have big problem with the 9.2 driver. The 9.1.5....

...> XEN SERVER2 > LVM / For each xen we create a new local LVM on each node, put them in a drbd and install an os (debian 4 or ubuntu 8). The xens are running as pvm. Everything works fine since over 4 months now. But we have some performance-Problems: Writing on the Xen-devices produces an iowait about 50 to 60% on the xen-processors. we have 3 szenarios tested: a) Xen on DRBD b) Xen on DRBD but disconnected c) direct mounted DRBD You can see the difference in Write pro Char and Write per Block. a: 3792 / 4011 b: 52037 / 103777 c: 57135 / 325002 See bonnie_result.txt for more data. We...

Kelly Lesperance wrote: > 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

Kelly Lesperance wrote: > 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

What is the HBA the drives are attached to? Have you done a quick benchmark on a single disk to check if this is a raid problem or further down the stack? Regards, Dennis On 25.05.2016 19:26, Kelly Lesperance wrote: > [merging] > > The HBA the drives are attached to has no configuration that I?m aware of. We would have had to accidentally change 23 of them ? > > Thanks, >