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-1
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3answers
3k views

iostat shows 100% utilization - what can be done to improve performance?

I have dedicated web server with CentOS. Recently, I get very high server load, probably caused due to IO bottleneck. iostat -mx 3 shows: avg-cpu: %user %nice %system %iowait %steal %idle ...
2
votes
2answers
315 views

How do I know if my disks are being hit with too many I/O reads or writes or both?

I know a bit about disk I/O and bottlenecks relating to this especially when relating to databases. How do I really know what the max I/O numbers will be for my disks? What metric might be available ...
2
votes
1answer
169 views

Linux buffer memory always stays at zero

One of my hosted server is a Xen guest running Debian and linux kernel 2.6.32 then 2.6.38. It has been running fine for quite some time (more than a year) but I recently noticed something weird. For ...
2
votes
1answer
354 views

Limit linux buffer usage by process

We have a production server running different process which take advantage of existing linux buffers to improve their performance, such as a mysql server. This server has exhaustive IO load. On this ...
2
votes
1answer
189 views

How can I determine the specific file referenced by fs_usage, which is listed by block

I was investigating a problem on a Mac OS X 10.6.8 Server, where users were complaining of access slowdowns. Network throughput slowed to a crawl. It felt like the server was overburdened. System ...
2
votes
1answer
2k views

High disk I/O activity in CentOS server

I have about 16 websites in a CentOS dedicated, and I am having some problems on high traffic hours, it seems to be a high disk I/O activity causing a general slowdown. I've installed atop and this ...
2
votes
1answer
216 views

inonice not working properly in xen dom0

I have a Xen Dom0 (3.2) with a bunch of domUs (paravirt). DomU VBDs are on local LVM volumes. Now I want to get backups of the LVM volumes using snapshots. I use rsync ioniced to idle (ionice -c3). I ...
1
vote
1answer
216 views

iotop does not show writes

What could be writing on the disk that iotop does not show? # iotop -a Total DISK READ: 8.19 M/s | Total ****DISK WRITE: 3.34 M/s**** TID PRIO USER DISK READ DISK WRITE> SWAPIN IO ...
1
vote
1answer
208 views

Does DFS-R actually write 100%+change to a file on the receiving server(s)?

I am analyzing DFS-R on Windows 2003 R2 and have come across a horrendous thing. It appears that when you append a small amount of data to a large (existing) file, the write cost on the server for ...
0
votes
1answer
103 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 ...
0
votes
1answer
340 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 ...
0
votes
1answer
41 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 ...
0
votes
1answer
40 views

File transfer slows down the server response

We are on Win server 2003 and we transfer the files across the same intranet either using CuteFTP or through mapped drives. The problem here is the file transfers start fast and get slower as time ...
0
votes
1answer
252 views

High cancelled_write_bytes, high IO load, concurrent memory-mapping

I have a software for persisting/retrieving data from files (a bit like database, but it's not exactly a database engine). It's not open source and the documentation is sparse, therefore I don't have ...
0
votes
1answer
121 views

replacement drive cage for power edge R710

Hi I'm performance tuning a DB server its a Dell R710 there is a very significant I/O bottleneck. Unfortunately the server was purchased with the 6 x 3.5 inch sata configuration which doesn't give me ...
0
votes
1answer
136 views

Sendmail greatly increases value of Total DISK WRITE

Sendmail is installed on the server. It sends an average of 6 emails at 3K per second and writes 18 files in /var/spool/mqueue-client. Because of this high disk writes iotop: Total DISK WRITE: ...
7
votes
0answers
63 views

rrdgraph generation fails on high IO load

We have a 4 core CPU production system which does a lot of cronjobs , having constant proc queue and an usual load of ~1.5. During night time we do some IO intensive stuff with postgres. We generate ...
2
votes
0answers
253 views

How can I optimize the Windows file cache so flushing a file is faster?

I have a third-party, object-oriented database server running on a Windows Server 2003 x64 machine with 24 GB of RAM. Except for some system processes and monitoring tools, the database server is the ...
1
vote
0answers
50 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 ...
1
vote
0answers
148 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 ...
1
vote
0answers
89 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) ...
1
vote
0answers
145 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 ...
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 ...
1
vote
0answers
46 views

Chrooted from LiveCD: Bad IO performace

my Ubuntu Server installation is broken, so I grabbed a Ubuntu Desktop CD, mounted my Ubuntu installtion on my hard disk and chrooted into it. But now my IO performance is really bad: # time dd ...
1
vote
0answers
450 views

I/O error on non-existent device?

Getting the following in /var/log/messages: Sep 17 10:38:53 server1 kernel: end_request: I/O error, dev sde, sector 0 Sep 17 10:38:53 server1 kernel: end_request: I/O error, dev sde, sector 63 Sep 17 ...
1
vote
0answers
464 views

Heavy disk write on a Debian VPS gives “ata1: lost interrupt (Status 0x50)”

I have a new Debian VPS that appears to fail almost every time I run a heavy disk write test on ext4 filesystem. The filesystem goes to read-only mode and "ata1: lost interrupt (Status 0x50)" is ...
0
votes
0answers
56 views

BUG: soft lockup - CPU#0 stuck for 23s! on XEN PV debian related to high i/o load

i am currently experiencing some problems with my Debian Xen System. It runns on an old opteron System with two Dual Core AMD Opteron(tm) Processor 275 CPUs. I am using image files (block devices) ...
0
votes
0answers
49 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 ...
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 ...
0
votes
0answers
395 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 ...
0
votes
0answers
278 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
70 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 ...
0
votes
0answers
33 views

Windows server 2008 I/O counters

For an I/O capacity study I'm working on, (on a windows server 2008R2 system) I'd like to gather absolute I/O counts for a given physical (or logical) disk over a specific period of time. When I look ...
0
votes
0answers
214 views

Weird Slowdown on I/O (4K blocks ?)

I have two identical servers, running Proxmox 2. 2x AMD 6 cores 2.3Ghz 64 Gigs of RAM DDR3 ECC (8*8) ASUS KCMA-D8 2x Seagate 2TB - (st2000dm001) One server is running perfectly fine. The other one ...
0
votes
0answers
156 views

High io usage and server hang

I have 3 dedicated server all with software raid-1 sata, centos or cloudlinux and cpanel. To all of them the last 10 days or so during cpanel incremental backup server has high io usage and hangs out. ...
0
votes
0answers
313 views

How to optimize Disk Activity for ClearOS?

I am looking for advice on how to optimize a ClearOS Enterprise 5.2 (+) install for disk i/o. For example, I installed my ClearOS on a thumb drive. I am seeing that the thumb drive flashes a LOT ...
0
votes
0answers
55 views

Determining Performance Limits

I have a number of windows processes that pass messages between them hat a high rate using tcp to local host. Aside from testing on actual hardware how can I assess what my hardware limit will be. ...