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-1
votes
0answers
14 views

Diferent I/O for different disks [on hold]

I have different disks in my computer (SSDs and HDDs). How can I permanently set differnt IO schedulers for different disks, so SSDs will use deadline scheduler and old-good HDD wil continue using ...
-2
votes
0answers
32 views

Cloud, grid, xen, performance [on hold]

I have some problems on my grid. I have 5 servers on it, running xen, but somehow, the IO on one of the machines (SQL server) are running extremely slow. But not just on VM, but on the servers too ...
0
votes
1answer
74 views

Linux - KVM - very slow disk io

The I/O performance of my new server is pretty low. I Googled and tried everything I can imagine. First of all, here are the Hardware Components: AMD Opteron(tm) Processor 6344 4x Seagate ...
2
votes
1answer
51 views

Is it possible to configure the Linux kernel I/O scheduler for an NFS mount?

On a normal block device you can change the i/o scheduler like this: # cat /sys/block/hda/queue/scheduler noop anticipatory deadline [cfq] # echo anticipatory > /sys/block/hda/queue/scheduler # ...
0
votes
1answer
36 views

Mongodump on Gridfs is killing the host IOs

I'm trying to make a mongodump from our production mongodb while the production is running. We have three production instances, one regular mongodb, one with very few gb of data on gridfs, one with a ...
4
votes
1answer
154 views

Linux page cache slows down IO on dual cpu server with 64GB ram

I have a massive problem with the linux page cache which slows down the IO. For instance if I copy a lvm partition with dd, linux cache the data in the buffers or caches (free –m). That is not the ...
2
votes
2answers
89 views

Azure IO performance

We have a number of Windows Server virtual machines that we use for .NET and Java development and QA. I find Azure attractive for the obvious reasons but mainly for the opportunity to reduce ...
3
votes
1answer
63 views

How can I measure complex I/O activity to develop realistic benchmarking? [closed]

I need to retrieve a few metric from my service server to benchmark another stroage solution. There are various options are provied by benchmark program(I choosed ...
0
votes
0answers
40 views

freebsd: disk i/o utilization statistic by user

Whether there some utils for collect/view statistic about disk I/O utilization by user in FreeBSD? After googling that question i found only sa, but in its manpage is not any information about ...
1
vote
1answer
52 views

can Iowait cause significant RAM consumption increase

I have a node.js process running continuously on a linux EC2 instance, it extracts data and stores it in mysql. Some reads are also performed on the database. The process can run well during hours or ...
0
votes
1answer
211 views

htcacheclean doesn't seem to be cleaning the cache

I'm running mod_cache with apache 2 on a fairly high traffic'd site. I've set the htcacheclean to run in demon mode every 10 minutes to keep the cache at 4GB. It's currently at 15GB and doesn't seem ...
2
votes
1answer
120 views

Setting I/O scheduler for SSD based RAID array on EC2 instances

I created a RAID array using the 2 local SSD drives on a EC2 c3.4xlarge instance. # mdadm --create /dev/md127 --level=0 --raid-devices=2 /dev/xvdf /dev/xvdg # mkfs.ext4 /dev/md127 # mkdir /data # ...
1
vote
0answers
43 views

__ticket_spinlock high cpu

We are having a strange problem on our Ubuntu 10.04 KVM infrastructure, where periodically, one of two vm webservers freaks out, with persistently high load, even if we restart the applications. (the ...
-2
votes
1answer
86 views

What dose these units means in zabbix?

When i try to set some items for my disk read and write, I found it by vfs.dev.read and vfs.dev.writefor zabbix-agent. This item contain a parameter named type which some of them are unknown for me. ...
2
votes
1answer
82 views

server hangs randomly without log entries

My physical server hangs randomly and I do not get any log entries during that time. So I let a script run: while true; do date >>/tmp/dates; sleep 1; done & disown After some minutes the ...
0
votes
1answer
201 views

report per-process IO stats with pidstat or sar

I'm trying to track io usage of a few "suspect" processes over time. Ideally would like to make those stats available via munin, or push directly to graphite. However, as a starting point it would be ...
1
vote
2answers
73 views

IOMeter showing hardly any data

I ran IOmeter on a Windows Server 2008 R2 SP1 server for 18 hours and when I clicked on "Stop current Test and Save Results" it stopped the worker processes (I only had 1). When looking at the ...
3
votes
1answer
57 views

Does ESX 5.X cache guest IO?

I am trying to find out if guest can see successful disk flush operation, but the host doesn't actually flush it to disk? How does ESXi work with guest I/O? Are they cached by ESXi before being ...
0
votes
2answers
77 views

How to benchmark maxCache 3.0 with SSDs? [duplicate]

We're a software development company and previously outsourced the HW side of business but now we're looking into building our own private cloud. We recently purchased a few servers, one of which is ...
1
vote
0answers
107 views

Why are pgpgin/s and majflt/s inconsistent in sar -B?

In sar -B ouptut, I would naively expect pgpgin/s to equal majflt/s multiplied by the system page size. From man sar: pgpgin/s Total number of kilobytes the system paged in ...
0
votes
1answer
140 views

Finding root cause of 99.99% iowait with 0% SWAPON

Users and DBAs are complaining that "Oracle is slow" on our OEL servers. The only thing I have found from the OS standpoint is that there are some strange IOWAIT stats from iotop. Output from iotop: ...
0
votes
1answer
32 views

How can I see which devices are used by a process?

iotop and iostat are great tools to see how much I/O is happening. But I haven't found out how these (or other) tools can show me the I/O rate per device and per process. So I'm looking for a way to ...
1
vote
0answers
64 views

Visualizing IO other then seekwatcher

Is there any other programs that can generate visuals/graphs/diagrams (movie and pictures) to visualize IO across a full device other then seekwatcher? NOTE: seekwatcher generates visuals(pic/movie) ...
2
votes
2answers
92 views

Simulate database I/O behaviour [closed]

I'm investigating some performance issue and I need a tool that can mock the same I/O behavior that a typical RDBMS is usually creating. I don't want to install a full blown RDBMS and mess around with ...
2
votes
1answer
102 views

I/O priority per LVM volume (cgroups)

How can I prioritize LVM volumes I/O performance using cgroups? I know I can use ionice to make changes at the process level but I wish to be able to do this per LV and not per process.
10
votes
1answer
194 views

how to do I/O sniffing

For sizing purposes I need to understand what requirements an application has to the I/O subsystem. I would love to do what I call I/O sniffing and obtain a list of events from the block layer like ...
1
vote
2answers
137 views

High Disk I/O on server reboot

A CentOS 5.8 machine has high Disk I/O upon starting up. The processes taking up disk IO are kmirrord, kjournald and pdflush. I have done the performed the following: 1) Mounted the filesystem with ...
1
vote
1answer
73 views

Munin graph Disk IOs for /dev/sda k unit interpretation

From Munin diskstats plugin Disk IOs for /dev/sda graph shows Max IO/sec -read/+write 1.75k/920.92. What does the k unit in Disk IOs graph mean?
0
votes
0answers
9 views

How can I conduct profiling Ubuntu 12.04 from OS Windows 7?

There are Windows 7 on one computer and Ubuntu 12.04 on another. I use WinScp for copying files and TightVNC for work with graphic display (from Windows). I want to estmate the IO performance in ...
0
votes
0answers
20 views

Server 2008 SP2 Network Share Strange Behavior

As stated in the title, I'm experiencing some erratic behavior on a network share. This share has files that are being updated in an automated fashion, using code I control, 24/7. 1) Perhaps the most ...
3
votes
1answer
155 views

IO related performance bottleneck on a LAMP server

I am administering a big LAMP server with some thousand users. About a week ago, things slowed down, and the only thing I see that the IO latency is increased dramatically. Users experience slow page ...
4
votes
1answer
193 views

How to calculate the required EBS PIOPS for our mongo server?

We want to use provisioned IOPS EBS volume on our mongo machines, I'm a bit confused on how to calculate the number of provisioned IOPS to use. Currently we're getting an average of 25 IOPS (read + ...
3
votes
1answer
335 views

How to monitor NFS load from userland?

Apologies if I'm not using the proper jargon (although I'm a longtime linux user, I'm not an admin) or if this is a FAQ (though searching SE got lots of hits, I didn't see anything quite like this ...
1
vote
0answers
106 views

Reason for high CPU time when executing fio

After weeks of troubleshooting some performance issues I have on my VPS running Ubuntu 12.04 LTS, I am getting closer to the conclusion that the problem is related to IO. When I have a considerable ...
0
votes
1answer
31 views

How to disable search body in dovecot?

We run mail server of 30k e-mail accounts (Maildir) with dovecot imap server. We suffer from high IO load, especially when a user starts to search large imap folders. Is any way of preventing search ...
0
votes
1answer
87 views

HDD operations slow server down, hangs completely

When running a tar cvzf command or copying large folders on the production server, the CPU load goes up to 8.5 (running on 8 cores) and the whole system hangs, neither apache is responding to any ...
0
votes
4answers
65 views

Limit copy speed

Unfortunately we have a pretty bad HDD performance on one of our servers and as soon as we start bigger copy process it stops to deliver any Apache response, which is really bad. Is there a way to ...
4
votes
4answers
660 views

Disk performance below expectations

this is a follow-up to a previous question that I asked (Two servers with inconsistent disk speed). I have a PowerEdge R510 server with a PERC H700 integrated RAID controller (call this Server B) ...
1
vote
1answer
79 views

low priority linux filesystem

Does anybody know of a some sort of (virtual) filesystem that will run as a low priority i.e. All other regular disk activity will take priority? The reason for this is an application I am developing ...
0
votes
1answer
535 views

Input/output error reading USB backup drive on CentOS 6.4

I'm suddenly seeing some strange behaviour on our USB backup drive that doesn't make sense to me: (2013-10-21 14:58:23 [root@newdc /]$ cd /mnt/backup/ (2013-10-21 14:59:03 [root@newdc backup]$ ls -la ...
2
votes
1answer
765 views

Windows “iowait” CPU utilization reporting

Does Windows account for and report "iowait" in the same manner as Linux? That is, processes enter "uninterruptible sleep" and their time spent is subtracted from "CPU free"? If so, which Perfmon ...
6
votes
3answers
335 views

How to keep subtree removal (`rm -rf`) from starving other processes for Disk I/O?

We have a very large (multi-GB) Nginx cache directory for a busy site, which we occasionally need to clear all at once. I've solved this in the past by moving the cache folder to a new path, making a ...
0
votes
0answers
342 views

Direct I/O on Linux

I'm trying to enable Direct I/O on /opt (/dev/sda6, ext4) on Linux Mint 13. What I'm trying is: mount -o dio,rw /dev/sda6 /opt as root. The system responds with: mount: wrong fs type, bad ...
2
votes
1answer
678 views

High iowait for unknown reason

I'm having a hard time figure out the reason cause high iowait on my server. This is log of iostat -xm 5 5 Linux 2.6.32-358.6.1.el6.x86_64 (prod-1.localdomain) 09/28/2013 _x86_64_ (16 CPU) ...
0
votes
0answers
223 views

High disk usage in CSRSS.EXE

I recently started working on the server for a certain software (Tango). The users complained that it recently became extremely low, so I used an application (ProcessHacker) to see the resource usage ...
0
votes
0answers
67 views

Two servers with inconsistent disk speed

I have two servers of identical spec (bought at the same time), except for the drive configuration: Server A: C: and D: drives are partitions on the same 2 disk RAID 1 E: is a 2 disk RAID 0 ...
1
vote
1answer
28 views

IO impact with symlinks

I have an NFS mount for web servers, I've moved log files to local storage to minimize IO load on NFS server but I've created symlinks for these logs (NFS share -> local storage). Is this still has ...
0
votes
2answers
183 views

How to maximize I/O on an OpenVZ VPS node?

I have an OVZ node with 46 VPSes. The SSD drive had 400Mb/s but after filling the node with VPSes the SSD drive sometimes drops to 40Mb/s. How can I prevent this from happening? Is there a way to ...
-1
votes
1answer
25 views

Apache2-server append a string to a JavaScript file before client receives the file

I never touched the Apache 'inner files', but now I need to add a string (that isn't static) to the end of some JavaScript files when serving them via Apache. What should I do / learn to achieve this? ...
1
vote
0answers
82 views

File I/O Throughput

I have an IBM x3650 M4 server (64-bit) running Ubuntu 13.04 Desktop (32-bit). I realize that this is a non-standard setup by it's being driven by other requirements. I am seeing slow file writes ...