Re: [CentOS] Possible to use multiple disk to bypass I/O wait?
On 06/15/2011 07:04 PM, Emmanuel Noobadmin wrote: > Looking at some very sparse notes I made on the decision, I think what > tipped the choice was that both qcow2 and lvm added overheads, but lvm > was on the whole system i.e. the host has additional processing on > every i/o whereas qcow2 overheads was only for guest i/o. I think you were misinformed, or misled. LVM should not present any noticeable overhead on the host. Using "raw" files to back VMs presents a significant overhead to guests; the host performs all IO through its filesystem. Using "qcow2" files presents even more overhead (probably the most of any configuration) since there are complexities to the qcow2 file itself in addition to the host's filesystem. > More > critically my note was the thought as well that it would be easier to > move a qcow2 file to another machine/disk if necessary than to move a > partition. It shouldn't be significantly harder to copy the contents of a partition or LV. The block device is a file. You can read its contents to copy them just as easily as any other file. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Possible to use multiple disk to bypass I/O wait?
On 6/16/11, Gordon Messmer wrote: > I think you were misinformed, or misled. That wouldn't be new for me as far as system administration is concerned :D >LVM should not present any > noticeable overhead on the host. Using "raw" files to back VMs presents > a significant overhead to guests; the host performs all IO through its > filesystem. Using "qcow2" files presents even more overhead (probably > the most of any configuration) since there are complexities to the qcow2 > file itself in addition to the host's filesystem. I was concerned about qcow2 vs raw as well since it seemed logical that qcow2 would be slower for the added functionality. However there was some site I found that showed that KVM with virtio, turning off host caching (or specifying write-back instead of the default write-through) on the file and doing preallocation on qcow2 files will make qcow2 as fast as raw. > It shouldn't be significantly harder to copy the contents of a partition > or LV. The block device is a file. You can read its contents to copy > them just as easily as any other file. Although the combination of ionice and atime seemed to have stopped things from going through the roof, I'll probably still try to convert one of them to LVM and see if that improves things even further. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] OT: high static in server room
On Thursday, June 16, 2011 12:56 PM, John R Pierce wrote: > On 06/15/11 9:44 PM, Fajar Priyanto wrote: >> On Thu, Jun 16, 2011 at 11:28 AM, Mike Williams >> wrote: >>> "Low humidity would be my first guess. The relative humidity in your >>> server room should be between 50% +/- 10%. Too high and you can get >>> condensation. Too low and you get electrostatic discharges." >> Oh! I thought it's 10% to 50%. >> So it's between 45%-55%. Uh-oh... need to put that fish tank asap. > > actually, its 40-60%, I believe. and you should have a humidifier as > part of your A/C, since cooling air sucks the moisture out of it. I > would NOT rely on a fishtank to provide any significant humidity. > Just get fish that spit and appropriate targets for said fish. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Odd issue with custom udev rule at boot
James A. Peltier wrote: > BTW: Can anyone try this to see if it is in fact a bug or not? > > Create a file called > > /etc/udev/rules.d/99-udev-override.rules > > that contains > > KERNEL=="tty[A-Z]*", GROUP="some_other_group_than_uucp", MODE="0660", > OPTIONS="last_rule" > > with mode of 0644 reboot and confirm that the group permissions > change or not. If you change the mode however you will see that the > mode *does* change. Works for me. Before: # ls -l /dev/ttyS* crw-rw 1 root uucp 4, 64 Jun 15 16:16 /dev/ttyS0 crw-rw 1 root uucp 4, 65 Jun 15 16:16 /dev/ttyS1 crw-rw 1 root uucp 4, 66 Jun 15 16:16 /dev/ttyS2 crw-rw 1 root uucp 4, 67 Jun 15 16:16 /dev/ttyS3 Created /etc/udev/rules.d/99-udev-override.rules containing: KERNEL=="tty[A-Z]*", GROUP="users", MODE="0660", OPTIONS="last_rule" After reboot: # ls -l /dev/ttyS* crw-rw 1 root users 4, 64 Jun 16 10:45 /dev/ttyS0 crw-rw 1 root users 4, 65 Jun 16 10:45 /dev/ttyS1 crw-rw 1 root users 4, 66 Jun 16 10:45 /dev/ttyS2 crw-rw 1 root users 4, 67 Jun 16 10:45 /dev/ttyS3 However, if I use a group name that isn't in /etc/groups (but is defined in say NIS), then the group is set to root after a reboot - but using the GID of that group works. James Pearson ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] OT: high static in server room
On 6/16/11, John R Pierce wrote: > actually, its 40-60%, I believe. and you should have a humidifier as > part of your A/C, since cooling air sucks the moisture out of it. I > would NOT rely on a fishtank to provide any significant humidity. Well, can't be so sure the fish tank won't do the job especially since he might be thinking along the lines of this or bigger http://www.clubelite.com.my/en/aquarium/images/aq2.jpg ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Wed, Jun 15, 2011 at 3:48 PM, Ron Blizzard wrote: > On Wed, Jun 15, 2011 at 2:37 PM, Tom H wrote: >> On Wed, Jun 15, 2011 at 5:58 AM, Ron Blizzard wrote: >>> >>> Mint/Ubuntu don't have an easy way to boot into the command line. >> >> To boot into "everything but X", you can append "text" to the kernel >> (grub1) or linux (grub2) line in the grub configuration. > > Okay, thanks. Good to know. I forget what "kludging" process I had to > go through to get Mint to boot into text, I think I disabled the X > server somehow. But even when I got to text mode, the Nouveau driver > had loaded, which is why I eventually had to blacklist it before > installing the proprietary nVidia driver. You're welcome. That's KMS for you; your consoles no longer are "pure text." CentOS 6 might be like that too given that F13 was (I can't remember whether F12 was). ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Wed, Jun 15, 2011 at 6:04 PM, Craig White wrote: > On Jun 15, 2011, at 12:33 PM, Tom H wrote: >> On Wed, Jun 15, 2011 at 4:50 AM, Craig White wrote: >>> >>> Like RHEL/CentOS, Ubuntu LTS is absolutely appropriate for server use. >>> In fact, it's sort of refreshing to set up a new server that isn't >>> overloaded with bloat from the very start. Setting up a new VMWare image >>> w/ Ubuntu Server takes at most 10 minutes whereas doing the same w/ >>> CentOS 5 takes almost an hour (easier just to clone my base install copy >>> kept for just that purpose). >>> >>> I actually use Fedora for my Desktop. It dual boots to Ubuntu but I >>> don't often use it. The only reason that I ever saw people using Fedora >>> for production was because the RHEL/CentOS software packages were so >>> completely out-of-date. >> >> Both CentOS and Ubuntu server installs take as long for me. Are you >> comparing similar levels of install?! > > I am generally interested in a basic install. On this Macintosh, > VMWare Fusion, installing 64 bit Ubuntu-server-amd64 it's about 10 > minutes. Installing 64 bit CentOS 5.6 x86_64 took about an hour. I > didn't time anything but I remember clearly. Of course the install from > Ubuntu was a single CD iso and CentOS was a DVD iso and the > bandwidth at my office is extremely good. > > A similar install is difficult since Ubuntu will have to indicate that > you want to install even openssh-server and CentOS (noting that > many of the decisions emanate from upstream) by default puts > on a full GUI and you have to knowingly trim down the packages > to attempt to minimize the installation. I don't really understand what you're doing but Ubuntu server and CentOS with a GUI are certainly not the same installs. For me the Ubuntu equivalent of a kickstart "@base" install and a CentOS kickstart "@base" install take pretty much the same time. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Wed, Jun 15, 2011 at 6:08 PM, Craig White wrote: > > those days will be over soon as even fedora has now switched to upstart > > CentOS 7 (based on upstream 7) will be a vastly different beast CentOS 7 will most probably have systemd not upstart. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Wed, Jun 15, 2011 at 4:47 PM, wrote: > > Or edit /etc/inittab to boot to runlevel 3, or just init 3 from the > command line (which you can reach via -f1) or I think you can > append 3 to the kernel line... That doesn't work on Debian/Ubuntu because runlevels 2-5 are the same. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Thu, Jun 16, 2011 at 07:17:38AM -0400, Tom H wrote: > On Wed, Jun 15, 2011 at 4:47 PM, wrote: > > > > Or edit /etc/inittab to boot to runlevel 3, or just init 3 from the > > command line (which you can reach via -f1) or I think you can > > append 3 to the kernel line... > > That doesn't work on Debian/Ubuntu because runlevels 2-5 are the same. I remember in Debian it was update-rc.d -f xdm remove I would guess something similar (gdm?) remove would work. -- Scott Robbins PGP keyID EB3467D6 ( 1B48 077D 66F6 9DB0 FDC2 A409 FA54 EB34 67D6 ) gpg --keyserver pgp.mit.edu --recv-keys EB3467D6 Xander: I don't like vampires. I'm going to take a stand and say they're not good. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Slightly OT: First Time KVM and LVM on Centos
On 6/16/11 1:56 AM, Gordon Messmer wrote: > On 06/15/2011 05:52 PM, Ljubomir Ljubojevic wrote: >> Drawback is that such KVM guest is not as easy to move to another host >> if current host can not boot. Copying image and config files will be >> much faster. > > There is no reason that should be true. Copying 20GB out of an LV > should take exactly the same amount of time as copying 20GB out of a file. What about the destination? Wouldn't it likely be harder to find a place to put the LV copy than space to write a file? Or can you copy back and forth? -- Les Mikesell lesmikes...@gmail.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
Scott Robbins wrote: > On Thu, Jun 16, 2011 at 07:17:38AM -0400, Tom H wrote: >> On Wed, Jun 15, 2011 at 4:47 PM, wrote: >> > >> > Or edit /etc/inittab to boot to runlevel 3, or just init 3 from the >> > command line (which you can reach via -f1) or I think you >> > can append 3 to the kernel line... >> >> That doesn't work on Debian/Ubuntu because runlevels 2-5 are the same. ?!?!?! 2 isn't much used, except as a set of steps. But 3 and 5 are the same in Debian/Ubuntu? That's not like *any* other version of *Nix. mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Config file semantics.
centos-boun...@centos.org wrote: > On 06/15/2011 10:41 PM, Mike A. Harris wrote: >> Personally, I find that indenting config files by 3 spaces has a lot >> of advantages to indenting them by 4 spaces although conventional >> wisdom might suggest otherwise. Who's with me on this? > > Three is evil, four even more. Two spaces and what do they say? It > will keep sanity close and evil at bay. Three won't work, we all know > she's a jerk. Four is a fail, it's missing a two so can never be the > grail. Just two FTW! Anything more is just a deadly sin. > > Regards, > Patrick > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos In .vimrc :set sw=4 :set ai In .bashrc alias diff='diff -bw' Hands everybody but OP a beer. Offers John R Dennison a gallon of gasoline to apply to OP Said gallon of gasoline has a pound of styrofoam dissolved in... Insert spiffy .sig here: Life is complex: it has both real and imaginary parts. Life is not measured by the number of breaths we take, but by the moments that take our breath away. //me *** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept for the presence of computer viruses. www.Hubbell.com - Hubbell Incorporated** ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Odd issue with custom udev rule at boot
- Original Message - | James A. Peltier wrote: | | > BTW: Can anyone try this to see if it is in fact a bug or not? | > | > Create a file called | > | > /etc/udev/rules.d/99-udev-override.rules | > | > that contains | > | > KERNEL=="tty[A-Z]*", GROUP="some_other_group_than_uucp", | > MODE="0660", OPTIONS="last_rule" | > | > with mode of 0644 reboot and confirm that the group permissions | > change or not. If you change the mode however you will see that the | > mode *does* change. | | Works for me. | | Before: | | # ls -l /dev/ttyS* | crw-rw 1 root uucp 4, 64 Jun 15 16:16 /dev/ttyS0 | crw-rw 1 root uucp 4, 65 Jun 15 16:16 /dev/ttyS1 | crw-rw 1 root uucp 4, 66 Jun 15 16:16 /dev/ttyS2 | crw-rw 1 root uucp 4, 67 Jun 15 16:16 /dev/ttyS3 | | Created /etc/udev/rules.d/99-udev-override.rules containing: | | KERNEL=="tty[A-Z]*", GROUP="users", MODE="0660", OPTIONS="last_rule" | | After reboot: | | # ls -l /dev/ttyS* | crw-rw 1 root users 4, 64 Jun 16 10:45 /dev/ttyS0 | crw-rw 1 root users 4, 65 Jun 16 10:45 /dev/ttyS1 | crw-rw 1 root users 4, 66 Jun 16 10:45 /dev/ttyS2 | crw-rw 1 root users 4, 67 Jun 16 10:45 /dev/ttyS3 | | However, if I use a group name that isn't in /etc/groups (but is | defined | in say NIS), then the group is set to root after a reboot - but using | the GID of that group works. | | James Pearson AHA! We use NIS here and I didn't even think that it wouldn't set the GROUP properly if it couldn't resolve it properly. James, you're brilliant! That fixed it. :) -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpelt...@sfu.ca Website : http://www.sfu.ca/itservices http://blogs.sfu.ca/people/jpeltier ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On Thu, Jun 16, 2011 at 02:15:28PM +0100, m.r...@5-cent.us wrote: > Scott Robbins wrote: > > On Thu, Jun 16, 2011 at 07:17:38AM -0400, Tom H wrote: > >> On Wed, Jun 15, 2011 at 4:47 PM, wrote: > >> > > >> > Or edit /etc/inittab to boot to runlevel 3, or just init 3 from the > >> > command line (which you can reach via -f1) or I think you > >> > can append 3 to the kernel line... > >> > >> That doesn't work on Debian/Ubuntu because runlevels 2-5 are the same. > > ?!?!?! 2 isn't much used, except as a set of steps. But 3 and 5 are the > same in Debian/Ubuntu? That's not like *any* other version of *Nix. > > mark Debian's configuration (at least wrt 3 and 5 being aliases for the same runlevel) is very similar to Slackware and Gentoo. The number and use of runlevels, traditionally, have not been defined (although the LSB has tried to address this) and different conventions have been used in various distributions (and, move widely, unices) - the use of 7 runlevels out of a possible 10 also appears to be more convention than any hard-and-fast rule. That said the convention used by CentOS does appear to be the most common (and closest to the LSB's definition) in use by Linux distros today. On System V and Solaris runlevel 5 is halt so you might get a nasty surprise if you were expecting X11! Laurence ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
Laurence Hurst wrote:
> On Thu, Jun 16, 2011 at 02:15:28PM +0100, m.r...@5-cent.us wrote:
>> Scott Robbins wrote:
>> > On Thu, Jun 16, 2011 at 07:17:38AM -0400, Tom H wrote:
>> >> On Wed, Jun 15, 2011 at 4:47 PM, wrote:
>> >> >
>> >> > Or edit /etc/inittab to boot to runlevel 3, or just init 3 from the
>> >> > command line (which you can reach via -f1) or I think
>> >> > you can append 3 to the kernel line...
>> >>
>> >> That doesn't work on Debian/Ubuntu because runlevels 2-5 are the
>> same.
>>
>> ?!?!?! 2 isn't much used, except as a set of steps. But 3 and 5 are the
>> same in Debian/Ubuntu? That's not like *any* other version of *Nix.
>>
> Debian's configuration (at least wrt 3 and 5 being aliases for the same
> runlevel) is very similar to Slackware and Gentoo. The number and use of
Haven't used slackware since, um, '95 or so.
> runlevels, traditionally, have not been defined (although the LSB has
In Linux? I mean, runlevel 3 was multi-user text mode as far back as Sun
OS - I can remember putting things into 3, because X would
while () {
crash
respawn
}
> tried to address this) and different conventions have been used in various
> distributions (and, move widely, unices) - the use of 7 runlevels out of a
> possible 10 also appears to be more convention than any hard-and-fast
> rule. That said the convention used by CentOS does appear to be the most
> common (and closest to the LSB's definition) in use by Linux distros
> today.
>
> On System V and Solaris runlevel 5 is halt so you might get a nasty
> surprise if you were expecting X11!
mark
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Re: [CentOS] Slightly OT: First Time KVM and LVM on Centos
On 06/16/2011 05:59 AM, Les Mikesell wrote: > What about the destination? Wouldn't it likely be harder to find a place to > put > the LV copy than space to write a file? Or can you copy back and forth? Yes, you can copy the content of a partition to a file and use it that way, or the reverse. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On 06/16/2011 06:15 AM, m.r...@5-cent.us wrote: > 2 isn't much used, except as a set of steps I think you're referring to Solaris' init. I'm not aware of any Linux init systems that start up by stepping through runlevels. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS-6 Status updates
On 6/16/2011 10:43 AM, m.r...@5-cent.us wrote:
>
>> runlevels, traditionally, have not been defined (although the LSB has
>
> In Linux? I mean, runlevel 3 was multi-user text mode as far back as Sun
> OS - I can remember putting things into 3, because X would
> while () {
>crash
>respawn
> }
Originally runlevel 2 was multiuser, 3 was multiuser with networking and
network daemons. Without serial terminals, that wouldn't make a lot of
sense...
>> On System V and Solaris runlevel 5 is halt so you might get a nasty
>> surprise if you were expecting X11!
I think adding 5 for X was a Linux kludge. And in the original sysV
design, I believe each runlevel was executed in sequence up and down.
That is, everything started in runlevel 1 and 2 started on the way to 3
and could be sequenced properly that way instead of jumping directly to
3 or 5 and having to have everything specified to start there.
--
Les Mikesell
lesmikes...@gmail.com
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Re: [CentOS] CentOS-6 Status updates
On 06/16/2011 12:41 PM, Les Mikesell wrote:
On 6/16/2011 10:43 AM, m.r...@5-cent.us wrote:
runlevels, traditionally, have not been defined (although the LSB has
In Linux? I mean, runlevel 3 was multi-user text mode as far back as Sun
OS - I can remember putting things into 3, because X would
while () {
crash
respawn
}
Originally runlevel 2 was multiuser, 3 was multiuser with networking and
network daemons. Without serial terminals, that wouldn't make a lot of
sense...
On System V and Solaris runlevel 5 is halt so you might get a nasty
surprise if you were expecting X11!
I think adding 5 for X was a Linux kludge. And in the original sysV
design, I believe each runlevel was executed in sequence up and down.
That is, everything started in runlevel 1 and 2 started on the way to 3
and could be sequenced properly that way instead of jumping directly to
3 or 5 and having to have everything specified to start there.
No. I worked with both SCO and ISC linux in the late 80's and early 90's and
run level 5 was used for X. In fact I think
it was used also in DGUX for X.
--
Stephen Clark
*NetWolves*
Sr. Software Engineer III
Phone: 813-579-3200
Fax: 813-882-0209
Email: steve.cl...@netwolves.com
http://www.netwolves.com
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Re: [CentOS] CentOS-6 Status updates
On 06/16/2011 12:58 PM, Steve Clark wrote:
On 06/16/2011 12:41 PM, Les Mikesell wrote:
On 6/16/2011 10:43 AM,m.r...@5-cent.us wrote:
runlevels, traditionally, have not been defined (although the LSB has
In Linux? I mean, runlevel 3 was multi-user text mode as far back as Sun
OS - I can remember putting things into 3, because X would
while () {
crash
respawn
}
Originally runlevel 2 was multiuser, 3 was multiuser with networking and
network daemons. Without serial terminals, that wouldn't make a lot of
sense...
On System V and Solaris runlevel 5 is halt so you might get a nasty
surprise if you were expecting X11!
I think adding 5 for X was a Linux kludge. And in the original sysV
design, I believe each runlevel was executed in sequence up and down.
That is, everything started in runlevel 1 and 2 started on the way to 3
and could be sequenced properly that way instead of jumping directly to
3 or 5 and having to have everything specified to start there.
No. I worked with both SCO and ISC linux in the late 80's and early 90's and
run level 5 was used for X. In fact I think
it was used also in DGUX for X.
Oops meant to say SCO UNIX and ISC UNIX not linux.
--
Stephen Clark
*NetWolves*
Sr. Software Engineer III
Phone: 813-579-3200
Fax: 813-882-0209
Email: steve.cl...@netwolves.com
http://www.netwolves.com
___
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Re: [CentOS] CentOS-6 Status updates
No. I worked with both SCO and ISC linux in the late 80's and early 90's and run level 5 was used for X. In fact I think it was used also in DGUX for X. I don't know about ISC UNIX (aka Interactive UNIX) but SCO did not use run level 5 for X. I cut my teeth on System V UNIX including SCO UNIX 3.2 and seeing X in runlevel 5 these days still feels wrong to me all these years later, though I have to come realize how convenient it is. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
