Discuss February 2008

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286 participants
340 discussions

versions of the mail command
by Nigel Kendrick 14 Feb '08

14 Feb '08

Hi Folks, I am running postfix on a CentOS 4 box and was playing around with mail autoresponders. I came across a wiki article that did the trick, except for the following line which is what sends the auto response: mail -s"Subject here" -a"From: <$2>" $1 < /etc/postfix/autoreply.txt The (minor) issue is that the mail command doesn't have the '-a' switch to change the sender so I just removed that part. It's not a biggie but is there an updated version of the mail command or an alternative I could use that would pick up the sender's name variable and use it? Thanks Nigel Kendrick

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ccache on CentOS?
by Niki Kovacs 14 Feb '08

14 Feb '08

Hi, Before using CentOS, I've spent a few years with Slackware. This distribution doesn't come with many packages, so I had the habit of building a lot of stuff myself. One of the first things I installed was ccache, a compiler cache that accelerates (re)building significantly. Has anyone ever setup ccache on CentOS? I'd be glad to find a little HOWTO. Cheers, Niki

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Re: Disk partitions and LVM limits - SUMMARY
by Peter Blajev 14 Feb '08

14 Feb '08

Thank you all for the help. I'm writing this summary message because of people requests. I haven't tried all of this. I just collected it and organized it. You've got a big storage. Now what? The short answer is: "Just connect it. It should work." I'll play safe by saying that the following applies to <10TB storage. Some people reported file systems of 80TB. Things to watch out for: - Make sure the driver you are using or the storage itself don't restrict you from making big partitions or file systems. - fdisk creates partitions up to 2.1TB in size. Use "parted" instead. - RHEL5 supports up to 8TB ext3 file system. To create bigger then 8TB use option "-F" and 4K blocks. Your options are: - If the storage is connected to a RAID controller you can use the controller to create smaller logical partitions. Then combine them with LVM. - If you really want to partition the drive use parted. While partitioning if you run into this message: === sdb: very big device. try to use READ CAPACITY(16). SCSI device sdb: 10248519680 512-byte hdwr sectors (5247242 MB) sdb: Write Protect is off === you can just ignore it. It's informational (based on a few people replies). If you don't like parted you can still use fdisk to create a few 2TB partitions and then use LVM. - Use LVM on the raw device. Don't partition. This is what I did and it worked for me. Make sure you wipe out the MBR first: dd if=/dev/zero of=/dev/sdX bs=512 count=63 (count=1 should work too but 63 won't hurt either) Create the pv, vg and lv: pvcreate /dev/sdX vgcreate <vg name> /dev/sdX lvcreate -L <size> -n <name> -v vg_name Now you have to create the file systems. Some people recommend XFS. If you try to create bigger then 8TB ext3 file system make sure you use option "-F" and 4K blocks: mkfs -t ext3 -F -b 4096 /dev/vg00/lvol01 For more information: http://www.centos.org/product.html http://kbase.redhat.com/faq/FAQ_103_11461.shtm The email thread "Disk partitions and LVM limits" in CentOS, RedHat and RedHat-Sysadmin mailing lists. Thank you Peter > Hi, > > I've got a DAS DELL MD1000 with a bunch of SATA drives in RAID 5 > configuration with total space of 5.4TB. This box is attached to a > CentOS5 system (kernel 2.6.18-53.1.6.el5). > > Any idea how to make this space usable? > Is there a limit how big a partition can be? What is the work around? > Is there a limit how big a file system ca be? > > I've tried to partition it but no matter how bug partition I create > fdisk spits out these messages on the console: > --- > sdb: very big device. try to use READ CAPACITY(16). > SCSI device sdb: 10248519680 512-byte hdwr sectors (5247242 MB) > sdb: Write Protect is off > --- > > I decided to not partition the drive and use LVM but the physical volume > stopped at 2TB. > > So, right now I can't use LVM because of this 2TB limit and I'm not sure > if I partition the drive how good these partitions are because of the > the message from fdisk. > > Any help or idea is highly appreciated. > > Thank you > Peter

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vncviewer and opening mail attachemtns kills the login
by Jerry Geis 14 Feb '08

14 Feb '08

I am running centos 5.1 I routinely vnc in from home (centos 5.1 NVIDA laptop) to work centos 5.1 NVIDIA based station. works fine 95% of the time. However, when I am running thunderbird mail client, and there is PDF attachment, clicking on the attachment it prompts to open with evince and I accept - my entire sessions is KILLED. When I reconnect I have been logged out and all my windows etc... are gone. Is there a reason for this behavior and if so how do I stop it? Thanks, Jerry

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using fping to find missing A records
by Rogelio 14 Feb '08

14 Feb '08

I have a specific question on how to do something, and a larger question addressing other "better" ways to do the spirit of what I'm asking. I'm setting up Nagios, and am trying to make sure that all of the subnets have A records, as IP addresses will be changing very, very rapidly, and when that day comes, I will not be here (but on another Nagios project). So, I'd like to create A records for each host. How do I "fping -a" a range of IP addresses, strip out the names of the name that the host replies with, and then ping that list of names? (You don't have to tell me how exactly, a general idea of which command line tools will do) I'm thinking something like: fping -g 192.168.1.0 192.168.1.255 -A | grep whatever > file, and then shove that file in another fping statement.

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Kernel update for Centos 4
by mbneto 14 Feb '08

14 Feb '08

Hi, I've noticed that we already have an updated kernel for the Centos 5. Any idea of when the same thing will happen for Centos 4 386 ? Thanks.

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Strange performance issues under CentOS 5.1
by Alfred von Campe 14 Feb '08

14 Feb '08

I am still running CentOS 4.6 on our production systems, but I am starting to plan the upgrade to CentOS 5.1. I have one test system running 5.1 that is the exact same hardware configuration as my 4.6 test system. One of our builds runs about 6 times slower on the 5.1 system, even though is uses less overall CPU time. I first suspected something wrong with the disk, but the results from bonnie++ show that the 5.1 system is slightly faster: Version 1.03 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- -- Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec % CP /sec %CP centos4.6 16G 35933 10 21301 5 46507 6 41.8 0 Version 1.03 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- -- Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec % CP /sec %CP centos5.1 16G 42015 14 21179 5 49863 4 91.6 0 Then I ran the build with "/usr/bin/time --verbose", and here are the results (first 4.6 then 5.1): Command being timed: "make" User time (seconds): 32.15 System time (seconds): 3.52 Percent of CPU this job got: 99% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:35.88 Command being timed: "make" User time (seconds): 22.05 System time (seconds): 3.11 Percent of CPU this job got: 11% Elapsed (wall clock) time (h:mm:ss or m:ss): 3:31.35 As you can see from the above, there is a lot of idle time on the 5.1 system. Finally, I ran the build with "strace -c", and here are the top ten lines of that output (again, 4.6 first and then 5.1): % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 53.81 16.804147 54916 306 58 waitpid 34.75 10.853461 82851 131 wait4 5.29 1.650844 9 177706 154581 open 1.61 0.503701 15 34408 read 0.91 0.283706 15 18607 write 0.60 0.185894 12 14919 10364 stat64 0.52 0.163340 10 16495 9079 access 0.47 0.146933 7 20581 mmap2 % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 60.07 15.173924 52687 288 58 waitpid 38.50 9.724412 83831 116 wait4 0.54 0.135194 7 19199 10705 access 0.36 0.090850 54 1681 1334 execve 0.27 0.067686 5 14423 10570 stat64 0.11 0.027676 1 24832 read 0.09 0.022339 0 155810 135765 open 0.03 0.007617 159 48 unlink Any suggestions as to what could possible be causing this? I am fresh out of other ideas to try. Alfred

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RE: [Iscsitarget-devel] Performance Question
by Joseph L. Casale 14 Feb '08

14 Feb '08

>Yes, jumbo frames, no irq coalescence, blockio and see if >you can get Backup Exec to use large io request sizes when >reading and writing the data. The larger the better. Ok, Jumbo's enabled on the switch and media server. For the sake of our sanity jumping back and forth, I am trying to enable jumbo's on the bonded pair in the target, # ifconfig bond0 mtu 9014 and it errors out? Any idea what I am doing wrong? Also, where do I tune irq coalescence? Thanks! jlc

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RE: [CentOS] Apache RPM's
by Les Bell 14 Feb '08

14 Feb '08

"Ross S. W. Walker" <rwalker(a)medallion.com> wrote: >> I agree whole heartily. It would go a long way though if Redhat provided independent certification of their products under these compliance banners. << RHEL 5 is Common Criteria certified against the Controlled Access Protection Profile (CAPP), Labelled Security Protection Profile (LSPP) and Role-Based Access Control Protection Profile (RBACPP) at EAL (Evaluation Assurance Level) 4+ (i.e. all requirements of EAL4 and some of EAL5), when running on certain hardware platforms (IBM). See http://www.commoncriteriaportal.org/public/consumer/index.php?menu=5 for the reports. That may be overkill for what you require, but if your system is certified and accredited, it usually stops auditors in their tracks. I agree with concerns about the inability of auditors to correctly interpret requirements. The Y2K panic provided lots of examples; I recall one junior auditor demanding that a network hub be replaced because it was not "certified Y2K compliant". Best, --- Les Bell, RHCE, CISSP [http://www.lesbell.com.au] Tel: +61 2 9451 1144 FreeWorldDialup: 800909

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Re: [CentOS] pvmove speed
by Ross S. W. Walker 13 Feb '08

13 Feb '08

Good suggestion, no it's not ESX, but it does do snapshots. -Ross ----- Original Message ----- From: centos-bounces(a)centos.org <centos-bounces(a)centos.org> To: 'CentOS mailing list' <centos(a)centos.org> Sent: Wed Feb 13 17:30:39 2008 Subject: RE: [CentOS] pvmove speed >I am facing the same issue with a migration of our VM machines >to a new iSCSI setup this year, around 1TB of VMs need to be >fork lifted over and I thought about exotic ways to move it >over, but I think in the end it will be by good ole backup exec >and tape. You're not running esx are you? Heh, I just did the same thing on a much smaller scale. Couldn't afford the long downtime while a copy took place so I shut the vm's off, snapped it and restarted it. I then scripted all files "without" 00000 in the name to rsync over (ssssslowly). I then only had to shut the vm off and sync the small snap's and restart the vm's on other storage. Only took a few minutes. jlc _______________________________________________ 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.

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Discuss February 2008