Discuss November 2007

discuss@lists.centos.org

256 participants
327 discussions

Re: [CentOS] IO causing major performance issues
by Ross S. W. Walker 16 Nov '07

16 Nov '07

Well the CFQ scheduler tries to do just that, but if the amount of io is overwhelming even it cannot compensate. Writes take longer then reads and for a mirror they have to happen on both drives before they can service another request. I suggest you put the temp database on a tempfs to avoid the problem. Set cfq scheduler on /dev/sda if it isn't already. Other then that you could try a different file system like xfs or jfs to see if that helps. -Ross -----Original Message----- From: centos-bounces(a)centos.org <centos-bounces(a)centos.org> To: CentOS mailing list <centos(a)centos.org> Sent: Thu Nov 15 19:29:20 2007 Subject: RE: [CentOS] IO causing major performance issues Of course IO can swamp the file system. My point is that the kernel should at least give enough time-slices to the other processes (like sshd) so we can still log in. It's not asking a lot from the kernel - to just log in via ssh really. -- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ antonio varni [ technology ] ESTALEA, L.P. 629 State Street #222 Santa Barbara, CA 93101 v 805.252.0115 f 805.899.2697 e avarni(a)estalea.com w www.estalea.com On Thu, 15 Nov 2007, Ross S. W. Walker wrote: > redhat(a)mckerrs.net wrote: > > Antonio Varni wrote: > > > > > > Hello everyone. > > > > > > I'm wondering what other people's experiences are WRT systems becoming > > > unresponsive (unable to ssh in, etc) for brief periods of time when > > > a large amount of IO is being performed. It's really starting to > > > cause a problem for us. We're on Dell PowerEdge 1955 blades > > > - but this same > > > issue has caused us problems on PE1950, PE1850, PE1750 servers. > > > > > > We're running Centos 4.5 right now. I know Centos 5 includes > > > ionice, more > > > io scheduler/elevator selections like deadlock/etc. Perhaps that would > > > fix this issue. We're running the latest PERC firmware. > > > > > > The specific issue I'm referring to at this point is on a > > > system running > > > mysql. All mysql data files are on a netapp filer but mysql's > > > tmp directory > > > is on local disk. Whenever a lot of temp tables are created (and thus > > > written and deleted from local disk quickly) we can't even > > > log in to the > > > machine - and our monitoring system gets all freaked out and we get > > > lots of pages, etc... FYI this is two disks with hardware raid 1. > > > > > > Is it just me? Or is this specific to Dell systems, or is this just > > > the state of the Linux kernel these days? Is there some magical patch > > > I can apply to make this issue go away :) > > > > > > > > > Thanks in advance for any insight into this issue. > > > > > > Antonio > > > > I have noticed similar behaviour on all sort of linuxes (in > > particular, ssh into the box is really slow when it's doing > > IO) and wondered why, but never really thought about > > investigating any further. > > > > Unfortunately, I do a lot of work with solaris and the funny > > thing is that I have *never* seen a solaris kernel exhibit > > this sort of behaviour. Even if it is installed on normal > > IDE/SATA disks. And, in fact, even if installed on the exact > > same hardware. > > > > > > Now I'm curious.....especially given that I'm right in the > > middle of pushing to get rid of solaris in favour of RHEL. > > It really depends what the system is doing, what services you are > running and how you have it configured. > > You had Solaris installed, what services was it running? > > You had Linux installed, what services was it running? > > Database temp tables and logs can generate an enormous amount of > io which can swamp the file systems of any system. > > I have seen it on Windows and Linux, so I don't see why Solaris > would be any different. > > You could always try a different scheduler to see if that helps, > for instance if you are using 'cfq' try 'deadline'. > > -Ross > > ______________________________________________________________________ > This e-mail, and any attachments thereto, is intended only for use by > the addressee(s) named herein and may contain legally privileged > and/or confidential information. If you are not the intended recipient > of this e-mail, you are hereby notified that any dissemination, > distribution or copying of this e-mail, and any attachments thereto, > is strictly prohibited. If you have received this e-mail in error, > please immediately notify the sender and permanently delete the > original and any copy or printout thereof. > > _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > http://lists.centos.org/mailman/listinfo/centos > _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.centos.org/mailman/listinfo/centos ______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.

1 0

Yum update fails
by Aron.Darling＠Emulex.Com 15 Nov '07

15 Nov '07

I updated my centos 4.5 server to centos last week and I am now getting errors when I attempt to do a yum update: [root@AJD-slag ~]# yum update Loading "installonlyn" plugin Plugin "fastestmirror" uses deprecated constant TYPE_INTERFACE. Please use TYPE_INTERACTIVE instead. Loading "fastestmirror" plugin Setting up Update Process Setting up repositories update 100% |=========================| 951 B 00:00 base 100% |=========================| 1.1 kB 00:00 addons 100% |=========================| 951 B 00:00 extras 100% |=========================| 1.1 kB 00:00 Determining fastest mirrors Traceback (most recent call last): File "/usr/bin/yum", line 29, in ? yummain.main(sys.argv[1:]) File "/usr/share/yum-cli/yummain.py", line 94, in main result, resultmsgs = base.doCommands() File "/usr/share/yum-cli/cli.py", line 381, in doCommands return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds) File "/usr/share/yum-cli/yumcommands.py", line 150, in doCommand return base.updatePkgs(extcmds) File "/usr/share/yum-cli/cli.py", line 672, in updatePkgs self.doRepoSetup() File "/usr/share/yum-cli/cli.py", line 104, in doRepoSetup yum.YumBase.doRepoSetup(self, thisrepo=thisrepo) File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 313, in doRepoSetup self.plugins.run('postreposetup') File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 153, in run func(conduitcls(self, self.base, conf, **kwargs)) File "/usr/lib/yum-plugins/fastestmirror.py", line 78, in postreposetup_hook repo.set('urls', repomirrors[str(repo)]) AttributeError: 'YumRepository' object has no attribute 'set' Any suggestions, Google has not been my friend today. Thanks, Aron

3 3

sdc1 without the sdc
by Scott Moseman 15 Nov '07

15 Nov '07

So I'm working with the iSCSI Initiator and an EqualLogic SAN. I'm not sure when this might have happened, but it appears that the /dev/sdc device is missing, yet the /dev/sdc1 partition exists AND is mountable. Is there a method to re-create the /dev/sdc device? I cannot dd or fdisk it, obviously, but I can mount the /dev/sdc1 partition and it works just fine. Not having the /dev/sdc is messing up my multipath setup (let alone whatever else might be affected). scsi3 : SFNet iSCSI driver Vendor: EQLOGIC Model: 100E-00 Rev: 2.3 Type: Direct-Access ANSI SCSI revision: 05 SCSI device sdc: 8417280 512-byte hdwr sectors (4310 MB) SCSI device sdc: drive cache: write through SCSI device sdc: 8417280 512-byte hdwr sectors (4310 MB) SCSI device sdc: drive cache: write through sdc: sdc1 Attached scsi disk sdc at scsi3, channel 0, id 0, lun 0 # ls -l /dev/sdc* brw-rw---- 1 root disk 8, 33 Nov 7 14:45 /dev/sdc1 Thanks, Scott

2 5

Installing skype in CentOS 5
by Andrew Allen 15 Nov '07

15 Nov '07

Having just upgraded my system from CentOS 4.4 to 5.0, I'm a bit disappointed that I still can't install skype from the skype repo using yum - when I try yum install skype, I end up with: libsigc++20-2.0.17-1.el5. 100% |=========================| 217 kB 00:13 ---> Package libsigc++20.i386 0:2.0.17-1.el5.rf set to be updated --> Running transaction check --> Processing Dependency: qt4-x11 >= 4.2 for package: skype --> Finished Dependency Resolution Error: Missing Dependency: qt4-x11 >= 4.2 is needed by package skype Any ideas please as to how this can be overcome so that I can install and run this very useful utility? Andy

4 13

central logging/analysis
by Johnny Tan 15 Nov '07

15 Nov '07

I'm interested in doing centralized logging & analysis of logs from my CentOS boxes. I messed around with syslog-ng and it seems like it's a better syslog. But I noticed most of the "usual suspects" of third-party repo maintainers (Dag, Axel, etc.) don't include it. Karanbir has an el4 version, but all my boxes are CentOS 5. I was going to go ahead and roll my own RPM (or, rather, rebuild Karanbir's el4 version), but it occurred to me to check what others were using in this space. Just sticking with plain old syslogd? Paying for splunk? Is there something else I haven't heard about? johnn

3 3

FTP with web interface
by Ugo Bellavance 15 Nov '07

15 Nov '07

Hi, I'm looking for a simple way to be able to administer ftp accounts on Centos4 (or 5, if needed). The best would be to have a web interface to do so, but I think I'd rather avoid using webmin... I've seen some tutorials for getting ftp servers to work with MySQL DBs, but I'd like to know how people are working. I'd like to have a separate set of users for ftp than for system. Thanks, -- Ugo Bellavance

4 3

IP range of Google Analytics server farm
by Simon Jolle 15 Nov '07

15 Nov '07

Hi Centos Users I would like to allow outgoing traffic to Google Analytics servers (destination port 80). I wish to do a iptables rule. How to whitelist all Google Analytics servers? cheers Simon -- XMPP: sjolle(a)swissjabber.org

3 3

Nagios on CentOS 4.5
by Jason Ross 15 Nov '07

15 Nov '07

First off I am a linux / CentOS newbies so go easy on me. Just curious if anyone out there is running Nagios on CentOS 4.5. I have now installed it on a second server due to issue but the issues have come back to haunt me. The OS is running on an IBM NetVista. Every thing in both installs is identical as are the problems. Once I have Nagios up and monitoring every thing hangs. Even a terminal will hang before it finally just locks up. The only thing that brings it back is a reboot. Even stopping the services doesn't work. Disk space seems fine and even during the hangs there doesn't seems to be anything taking up a tremendous amount of resources. After a reboot every thing works fine for several hours. Any guesses or suggestions? Jason Ross

6 11

AW: [CentOS] Linux PDA/smartphone sync?
by Marc R. 15 Nov '07

15 Nov '07

Hi Ugo, Maybe "Funambol" could do the job :-) Many Devices will work with this Software, But i'm unsure if your Device will work. For Details you should have a closer look to: http://www.funambol.com/opensource/ Regards, Marc Rebischke ----- Ursprüngliche Nachricht ----- Von: Ugo Bellavance <ugob(a)lubik.ca> Gesendet: Mittwoch, 14. November 2007 22:13 An: centos(a)centos.org Betreff: [CentOS] Linux PDA/smartphone sync? Hi, I think I'll finally be able to move away from windows... I just installed linux and I'm wondering what people use as smartphones/PDA. I currently use a motorola V710 phone, which allows me to sync my contacts and calendar, which is all I need. I may change it soon, so I'd like to know what is best to work with linux (I use evolution right now, connected to an exchange (eventually scalix) server). I'm trying to get moto4linux to work, but I'm not even sure if I'll be able to sync my calendar + contacts with this. Any advice? Regards, -- Ugo Bellavance _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.centos.org/mailman/listinfo/centos

1 0

OT: Scripting with sudo password
by James A. Peltier 15 Nov '07

15 Nov '07

Completely off topic, but I'm sure someone out there is using scripts that require a sudo password of some sort, so I'll ask. What are people doing to automate tasks that required sudo passwords in order to run? sudo without a password is not an option for me, but I would like to be able to enter the password once have it saved and then read back when sudo is required. something like run_on_all_hosts perform_sudo_command script prompts for password script lauches on all hosts and passes password when required. Any examples? -- James A. Peltier Technical Director, RHCE SCIRF | GrUVi @ Simon Fraser University - Burnaby Campus Phone : 778-782-3610 Fax : 778-782-3045 Mobile : 778-840-6434 E-Mail : jpeltier(a)cs.sfu.ca Website : http://gruvi.cs.sfu.ca | http://scirf.cs.sfu.ca MSN : subatomic_spam(a)hotmail.com

7 9

← Newer
1
...
16
17
18
19
20
21
22
...
33
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Discuss November 2007