General :: Monitor Disk Reads Versus Writes?
Jul 2, 2010We are graphing various system parameters using Cacti. One of our graphs shows hard drive reads and writes. A question came up: why do we need this graph?
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General :: Difference Between Buffered Disk Reads And Cached Reads?
Jul 13, 2011I was analyzing the Disk read using hdparm utility. This is what i got as a result.
Code:
# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 108 MB in 3.04 seconds = 35.51 MB/sec
Code:
# hdparm -T /dev/sda
/dev/sda:
Timing cached reads: 3496 MB in 1.99 seconds = 1756.56 MB/sec I m not sure what does Cache read and buffered disk read mean.
General :: Program That Reads Multiple Pipes / File Descriptors And Writes To Standard Output
Feb 23, 2011Is there already a program that reads multiple pipes or file descriptors and writes to the standard output (not splitting lines).Like cat, but reading all files simultaneously and preserving lines.It is needed to avoid coding of select/epoll loops or using multithreading in simple programs. Like "select loop for bash".
View 1 Replies View RelatedUbuntu :: Samba Slow Writes To Server But Fast Reads
Jul 1, 2010I have a fileserver running 10.04 server 64bit and samba. I connect it to my desktop which is 10.04 desktop 64bit.I have the server mounted on my desktop in fstab as://10.0.0.2/share /media/share cifs guest, uid= 1000.Up until 30 June 2010 it was all fine. Now when I write the server it is very slow e.g. 2Mbps though when I read I get >100Mbps so I think my network is still ok. If i use nautilus smb://10.0.0.2/share I can write at >100Mbps and also read at >100Mbps...So any ideas why the write speed via the fstab mount samba has started to go really slowly in the last couple of days?
View 6 Replies View RelatedCentOS 5 Hardware :: Determine IO Size During Reads And Writes To A Storage Device
Nov 19, 2009Is there a way to determine the IO size that is being used for reads and writes to an attached storage device? I am trying to pattern the IO sequences to storage. I have seen mentions to max_sectors_kb but the notes indicated that changing this value did not change the IO size to the storage.
View 1 Replies View RelatedCentOS 5 :: RAID 10 "slow" Reads But Good Writes
Feb 28, 2011I have a 6 disk mdadm RAID 10 array of Western Digital RE3 drives. IOZone and all the other tools I have tried are showing pretty lackluster reads for a six drive RAID 10 array, in the area of 200MB/s. Writes are closer to what I'd expect in that area, around 340MB/s. These drives fly with an Adaptec RAID controller, but as soon as I stick them in an mdadm array, the reads just aren't what I'd expect.
I am using what I believe to be optimal settings:
-C /dev/md2 --chunk=1024 -n 6 -l 10 -p f2 /dev/sda5 /dev/sdb5 /dev/sdc5 /dev/sdd5 /dev/sde5 /dev/sdf5
-b 4096 -E stride=256,stripe-width=768
Ubuntu :: System Becomes Almost Unusable During Disk Writes?
Apr 12, 2010I'm using 9.10 Desktop 64bit on a Dell Latitude D830. I have 4 gigs of RAM and a 7200 rpm sata hard drive. Everything works pretty well, video, sound, and network. Flash isn't as smooth as in Windows but I assume that's a Flash/64bit thing and not necessarily an Ubuntu thing.
However, one area of performance still lags far behind my Windows XP experience, and that's disk writes. For instance, when I'm copying a large amount of information from a USB drive or from my Windows partition to my native partition, I can barely switch windows until the task is complete, nevermind trying to surf the Web. I thought that that might be related to the slow performance of the ntfs driver, but recently I have been doing a lot of work with VMWare, and I get the same result when trying to pause virtual machines - it writes a largish amount of information to disk in a short amount of time and I can't do much until it finishes.
Here are some things I looked at based on other threads to try to debug my issue:
~$ sudo hdparm /dev/sda
/dev/sda:
multcount = 8 (on)
IO_support = 1 (32-bit)
readonly = 0 (off)
readahead = 256 (on)
[Code].....
That disk read speed is a little faster than average - several more tests showed it hovering around the 66 MB/sec range. Of the other info, I see that UDMA is on which I understand is good, but if there is something else there that I should fix I don't see it.
I know that my computer can handle these tasks (at least the vmware stuff) without such a significant interface slowdown because in XP I did it with less RAM than I have now. Is this just the way that the linux kernel scheduler fails to account for UI needs?
Ubuntu Servers :: IOwait High, No Disk Writes, Server Hangs?
Jul 24, 2011I run a website that a very steady flow of traffic and Im seeing recent issues that I just dont like. Server is 10.04.2 on a supermicro i7-950/6gb RAM with two 500gb Samsung F3 drives in a software RAID1 (1x5400, 1x7200) and for several weeks, its been running very well. Recently, Im seeing the server hang for 5-20 seconds. IOwait goes through the roof, nothing can write to the disk. Apache logs stop, redis fails to rebuild caches, mysql errors and then it continues and moves back to normal operation
/ is ext4, the kernel was 2.6.32-server-x64 but since updating to 2.6.38-server-x64, the issue has dropped from maybe once per 10 minutes to once per 15 minutes. 3 IOstat copy/pastes show this when it hangs.
Code:
Total DISK READ: 0.00 B/s | Total DISK WRITE: 0.00 B/s
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
[code]...
No smart errors or smart diags show any issues with any of the disks and kernel.log shows near nothing other than a process hang, 120 seconds about 5 days ago.
Ubuntu Servers :: Raid1 Reads At Single Disk Speed?
May 3, 2011im on 10.10(desktop) and mdadm was v2.8.1 from 2008, very out of date so i tried 3.2.1 -> no change. mdadm raid1 read speeds are the same as single disk. note i used the tests in the disk utility benchmarking tool at first --these showed raid 5 atleast to be much better but when i tried dd reads raid5 dropped off with larger data to almost the same (slow) speed as raid1. compare:
[code]....
using two partitions will be enough to show raid1 performs at single disk speed. I dont really want to use a 4 disk raid0 just to get the read speed i should be able to get with raid1 as i dont really care about the size loss. I would of course use raid10 but i have found this suffers from the same problem (achieve same read speed as 2 disk stripe). So whilst im shocked others aren't reporting this, unless there is some obscure reason why my system would give these results i think raid1 in not behaving as it should.
Ubuntu :: RAM Usage - Top Versus System Monitor
Jan 18, 2011I'm doubtful about my Ubuntu's ram usage, as I'm getting different values in top and System Monitor:
System monitor:
Top:
What could be causing this? What should I trust, Sysmonitor or top?
Ubuntu :: Disk Cloning With Clonzilla Versus DD
Jan 1, 2010Is there any reason why is DD still prefer over clonezilla for disk cloning?
View 6 Replies View RelatedHardware :: GeForce NV34 FX-5200 Versus The Samsung SyncMaster 731N Monitor
Apr 13, 2010I have changed to Debian 5.0 on this old Gateway box, and the video is the GeForce NV34 FX-5200. I set it up with a Dell monitor and everything works great, I have several screen resolutions avail. But now I changed to the Samsung SyncMaster 731N and now I have only 2 resolution choices. 600x400 and 800X600. Besides move back to the Dell, how can I get the card to work with the monitor?
View 3 Replies View RelatedGeneral :: Monitor Disk Mounts ?
Oct 1, 2010What is the best way to detect disk mounts?
I'm setting up a system to automatically detect disk mounts, so I'm looking for a file or something where disk mounting is recorded.
There are several files that look promising, but I am a LINUX novice, so I don't quite understand the exact roles each play:
Of the above files, etc/rmtab looks most promising.
General :: Good Software To Monitor Disk Io , Memory And Cpu Use?
Jul 19, 2011I'm developing a website. I was wondering if there are any tools out there that make it easy to log and graph usage statistics of how my cpu, memory, disk and network are used.
I need to somehow know when I need to scale up / when I'm going to get problems soon.
I found http://sebastien.godard.pagesperso-orange.fr/
(command line thingy, not so useful because I'd have to write my own graphics and logging layer on top of it..)
General :: Where To Writes The Commands
Feb 1, 2010where to writes the commands if i am using fadora 11?
View 2 Replies View RelatedGeneral :: Read - Writes Are Slow On NFS
Oct 23, 2010Read/writes are slow on NFS.How can we diagnosing the issue, what commands are used for the error finding
View 8 Replies View RelatedGeneral :: Find Directory With Frequent Writes And / Or Deletes?
Jun 20, 2011Is there a way under linux to find out directory with frequent writes and/or deletes?
I'm using Ubuntu and recently bought SSD. I moved /tmp to ramdisk and did some other tweaks to avoid wear. But I was wondering if there's a way to pinpoint hotspots in filesystem where files are often written. For example webserver's log directory with many appends every minute or user's download directory where he downloads gigabytes of stuff only to be moved elsewhere soon after finishing.
I came across inotify which could probably do the trick but it seems it'd require lot of scripting which I'm not very familiar with
General :: Debian Sqeeze Pressing E Key Writes 0128
Mar 8, 2011I hav Debian Sqeeze, and not knowing what I did, it suddenly starts to consider all pressing of e key as 0128. Also some other key, which I don't know currently. I use different layout, however it happens on others too.
View 2 Replies View RelatedGeneral :: CD Reads On Win98 But Appears To Ber Empty On Fedora14
Apr 27, 2011I got a CD with a book - doc files.When I look at it with nautilus or with wine notepad it tells me that the CD is empty. capacity 49.4 MB. It does show the name of the CD BOOK2XTRAS - so at least the name field in the first sector is where it is supposed to be.When I boot to my 2nd drive - an old win98 sys - it sees all the files on the CD. Same CD drive in each case. I go to another fedora computer I have and it does n.ot see the contents either.
View 5 Replies View RelatedGeneral :: Shell Script That Reads From Parameters File?
Nov 3, 2009what I am trying to do but I am not sure exactly how to do it. I want to write a shell script that will replace certain values in a file with environment specific information that it pulls from a parameters file. The paramaters file looks like the following...
[dev]
ip=10.15.109.41
name=dev1.mydomain.com
[code]...
General :: Bash Script That Reads Files In Directory And Processes Them?
Jan 22, 2010I am trying to create a function within my .bashrc that will process all of the files that do not end with .sh within a directory and execute them.The following is what I have so far. I am missing a way of excluding files that end with .sh though.
function startall {
for file in /etc/init.d/*.; do
"${file}" start
[code]...
General :: Write A Script To Execute A Fortran Code That Reads In Parameters From Keyboard Typing?
Apr 18, 2011I am trying to write a script (especially C-shell) to execute a fortran code that reads in parameters from keyboard typing. I will have to process this .F code for many times with the parameters the same for all my data files, therefore, I don't have to type in everytime I execute the .F code. But I don't know what is the command in c shell to read in a text files that contains all the parameters I want and can make the shell read in appropriately to feed the .F code.
View 3 Replies View RelatedSoftware :: Monitor I/O But Not Disk - CPU?
Aug 18, 2010I have googled for linux io monitoring, but most of the search results are about disk I/O monitoring, while i need to monitor I/O in general, e.g. bus master I/O, etc. and in particular, data transfers to/from video card, i.e. how much data is being transferred, when, etc.. Is there a tool for this?
View 3 Replies View RelatedGeneral :: GUI Versus RPM And APT
Apr 6, 2010Why should I concern myself only with a graphical front end rather than learning APT or RPM? Or are those really, really hard to learn?
View 7 Replies View RelatedUbuntu :: "HDD Regenerator" Versus "Disk Utility"
Aug 14, 2011Dist Utility says that my HDD has 65545 bad sectors I checked my HDD by "HDD Regenerator" and it reported no bad sector! which one is correct?
View 9 Replies View RelatedGeneral :: Bash Versus Pinyin ?
Aug 23, 2010I am trying my hand at Bash scripting. I have a file with lots of pinyin, which is the romanized version of Chinese characters and words. A typical entry looks like this,
"7 shuo1 to speak"
Seven is the number of the entry shuo is the pinyin, 1 is the tone mark and is the Chinese character.
What I would like to do is change the format so that it looks more like this:
7 shuo 1
Each field needs to be re-assigned to a variable in an array and then printed to the screen and saved to a file in the same order it was input. This is to prepare the data for another project I am working on in imagemagick.
I have spent all day looking at linux man pages and have very little to show for my efforts. What is the best way to approach this? grep, awk, sed...?
General :: Slackware Versus Archlinux ?
May 19, 2010I have a Dvd of Slackware as well as an Iso image of Arch.
All i know about the difference between Slackware and Arch is the stability, i.e. Slackware is more stable than Arch !
Is that all or there is some other difference which should be considered ?
Which one out of the above two, should i go for and why ?
General :: Unmount Versus Hide
Oct 25, 2009trying to do a multiboot, just for fun Now I installed Foresight Linux, which was not such a good.Foresight is based on rpath and uses Conary as update system Now Conary destroyed all other linux systems installed on the other partitions. Now I found that there is something such as hide and unmount but have read several pages full of it but still have no idea what is the difference between the two and more important, how to use this as most explanations seem to complicated How can I hide partitions for a booted linux operating system so it is unable to see it, use it or even mount it when it tries
View 2 Replies View RelatedRed Hat / Fedora :: Software Or A Script - Monitor If Disk Is Mounted Or Not
Oct 11, 2010I need a utillity which wil monitor if disk is mounted or not. Is there a software or a script for that? I use fedora 12. Something which will send an email if disk is not mounted. I use encrypted disk, when power is off, after booting on, disk is not mounted on and I don't wan't to be automatically mounted on.
View 1 Replies View RelatedGeneral :: Sudo Versus SU - SAX2 Command?
Jun 3, 2010I've been using SuSE for a while and something has been bugging me. Not a show stopper, but nevertheless, an interesting one. Most tutorials, forum posts, etc. recommend using a sudo command to accomplish stuff. For example:
Code:
sudo make install
sudo vi file
However, this does not always work. For instance, I was recently working on a resolution problem with my ViewSonic VX922 - it would only display at 1024x768 rather than the native 1280x1024. Viewing some posts, I found the command "sudo sax2 -r". What I discovered is that there seems to be a big difference between sudo and su
Code:
drkhelmt@SPACEBALL1:">sudo sax2
root's password:
sudo: sax2: command not found
drkhelmt@SPACEBALL1:">su
Password:
SPACEBALL1:/home/drkhelmt: #sax2
SaX: Checking update status for intel driver
SaX: initialization already done
SaX: cal [ sax2 -r ] if your system has been changed !
SaX: startup
SaX: X server:0.0-> grant
SaX: importing current configuration
SPACEBALL1:/home/drkhelmt: #
So the question, why does the command sax2 (and others) work when after the su command rather than a sudo?