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0
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19 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
31 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
22 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
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1answer
44 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 # ...
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0answers
24 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
37 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
74 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
107 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
36 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
48 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
48 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 ...
0
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0answers
38 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 ...
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1answer
64 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
20 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
33 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
72 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
60 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
169 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
88 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
50 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?
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0answers
8 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
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0answers
18 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
120 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
116 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
166 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
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0answers
53 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
27 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
76 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
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4answers
60 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
315 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
68 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
268 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
410 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
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3answers
288 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
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0answers
226 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
401 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) ...
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0answers
153 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
64 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
25 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
150 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
21 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
76 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 ...
0
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0answers
76 views

Ubuntu server 13.04 frozen on high I/O load

I have Ubuntu server 13.04 running kernel Linux server3 3.8.0-26-generic #38-Ubuntu SMP Mon Jun 17 21:43:33 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux It was running fine 2 weeks with no problem, but ...
3
votes
2answers
338 views

linux: how to simulate hard disk latency? I want to increase iowait value without using a cpu power

Is it possible to set an arbitrary delay for I/O operations? I would like to learn how do iowait and disk %util impact the performance. There are a lot of tools to stress the disk (bonnie++ etc.) but ...
0
votes
0answers
87 views

Server Event Log ID 26

I’m running Windows Server 2008 with MPIO clustered shared volume, Failover clustering and TSM running Incremental backup at 3am every day. I was looking at event log as part of my routine and found ...
2
votes
2answers
132 views

CentOS 5 extremely slow when is running a download

When my server is downloading a file or executing other IO operations the other server functions become extremely slow (almost locked). Even other functions that do not use the network. When a ...
0
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3answers
190 views

Dramatic disk I/O performance difference for two disks on same machine

A small machine (1 core, 1 GB RAM, CentOs 6.3) virtualized via Citrix Xen has 3 virtual disks with very different sizes. > cat /etc/fstab (snippet) ... /dev/mapper/vg_stagingnfs-lv_root / ext4 ...
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0answers
104 views

XenPV Server showing file system in read only mode after reboot

I am running solus vm xenpv vps for hosting my websites yesterday i have increased RAM of this vps than i reboot this it start very slow this server hosts cpanel websites but all websites showing ...
14
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4answers
945 views

How do limit disc i/o during backup?

I have a cron that basically do a simple "tar zcf" in the night. The server has: 8 Cores - Intel(R) Xeon(R) CPU E5606 @ 2.13GHz 25GB RAM Ubuntu 12.04.2 LTS Hardware RAID 1 (LSI Logic / Symbios ...
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2answers
212 views

How to reduce I/O on EC2 micro instance running wordpress

I have been running a very small wordpress site on Amazon EC2 for about 2 months, using the free tier micro instance. I have been getting billed a few dollars each month for going over the disk I/O ...