From: Mark Milhollan Sent: April 21, 2015 05:35
On Mon, 20 Apr 2015, Hugh E Cruickshank wrote:
CentOS 6
From ''man fstab'' ...
The sixth field, (fs_passno), is used by the fsck(8)program to determine the order in which filesystem checks are done at reboot time. The root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2. Filesystems within a drive will be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the hardware. If the sixth field is not present or zero, a value of zero is returned and fsck will assume that the filesystem does not need to be checked.
Thanks but changing the order of execution or executing them in parallel does not help with executing them one per reboot.
Regards, Hugh
On Tue, Apr 21, 2015 at 11:01 AM, Hugh E Cruickshank hugh@forsoft.com wrote:
Thanks but changing the order of execution or executing them in parallel does not help with executing them one per reboot.
Why do you care about running them at the same time when it doesn't take longer to run them all in parallel? Except I think the root filesystem normally runs first. So you might want to stagger it vs. everything else.
And unless you reboot frequently you are probably hitting the time setting, not the mount count.
On Tue, April 21, 2015 11:19 am, Les Mikesell wrote:
On Tue, Apr 21, 2015 at 11:01 AM, Hugh E Cruickshank hugh@forsoft.com wrote:
Thanks but changing the order of execution or executing them in parallel does not help with executing them one per reboot.
Why do you care about running them at the same time when it doesn't take longer to run them all in parallel? Except I think the root filesystem normally runs first. So you might want to stagger it vs. everything else.
And unless you reboot frequently you are probably hitting the time setting, not the mount count.
How frequently does one reboot (CentOS) Linux? Well, my observation is: every 30-45 days there is either kernel or glibc update so you have to reboot. This makes it about 10 reboots a year, so you are pretty much close to hitting mount count as much as time from last fsck for ext[2,3,4].
As it was already mentioned: XFS is marvellous. I use it forever for huge filesystems on Linux boxes. I remember howto by Russel Ingram was titled "Linux + XFS HOWTO. Linux on Steroids"...
Valeri
++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
From: Les Mikesell Sent: April 21, 2015 09:19
Why do you care about running them at the same time when it doesn't take longer to run them all in parallel? Except I think the root filesystem normally runs first. So you might want to stagger it vs. everything else.
I am trying to avoid running them at the same time in an effort to avoid 70 minute boot times (which is what happened on the weekend). I accept that fscks are required on a periodic basis and I am willing to reboot more often to achieve these but I would like to minimize downtime (during the reboot) where possible.
And unless you reboot frequently you are probably hitting the time setting, not the mount count.
This is in fact what transpired on the weekend and I would leave this in place as a protective measure.
Regards, Hugh
On Tue, Apr 21, 2015 at 11:40 AM, Hugh E Cruickshank hugh@forsoft.com wrote:
From: Les Mikesell Sent: April 21, 2015 09:19
Why do you care about running them at the same time when it doesn't take longer to run them all in parallel? Except I think the root filesystem normally runs first. So you might want to stagger it vs. everything else.
I am trying to avoid running them at the same time in an effort to avoid 70 minute boot times (which is what happened on the weekend).
How many filesystems do you have? If you look at ./etc.fstab, everything where the final number is '1' (normally just the root filesystem) should complete first, then everything with a 2 will run at once. If the other mounts are each on different drive/spindles they won't conflict with each other and will complete in the same time as running just the largest one of them. If you are running fscks of partitions on the same drive in parallel it will obviously go slower.
From: Les Mikesell Sent: April 21, 2015 09:54
On Tue, Apr 21, 2015 at 11:40 AM, Hugh E Cruickshank wrote:
I am trying to avoid running them at the same time in an effort to avoid 70 minute boot times (which is what happened on the weekend).
How many filesystems do you have?
It varies from system to system but is typically 8-10.
If you look at ./etc.fstab, everything where the final number is '1' (normally just the root filesystem) should complete first, then everything with a 2 will run at once. If the other mounts are each on different drive/spindles they won't conflict with each other and will complete in the same time as running just the largest one of them. If you are running fscks of partitions on the same drive in parallel it will obviously go slower.
I am aware of that. With the exception of /, /boot and /home which are on one spindle (actually a hardware mirrored pair) the remaining filesystems are on separate drives (actually hardware mirrored pairs or RAID 10 arrays). The largest of the filesystems (four of them) share a common SAS controller, data channel and external disk array hardware (HP D2600) so running these in parallel might not be as effective as they could be.
Regards, Hugh
On 04/21/2015 09:40 AM, Hugh E Cruickshank wrote:
I accept that fscks are required on a periodic basis and I am willing to reboot more often to achieve these but I would like to minimize downtime (during the reboot) where possible.
Why do you accept that? The default behavior for filesystems set up by Red Hat tools (anaconda) is not to fsck. Not by mount count, nor by time. The default behavior for e2fsprogs was changed to disable periodic fsck in Feb 2011. CentOS 6 includes a version of e2fsprogs from before that change, but the filesystem is considered very stable, and the periodic fsck is not generally considered necessary.
From: Gordon Messmer Sent: April 21, 2015 10:30
On 04/21/2015 09:40 AM, Hugh E Cruickshank wrote:
I accept that fscks are required on a periodic basis and I
am willing
to reboot more often to achieve these but I would like to minimize downtime (during the reboot) where possible.
Why do you accept that?
Every article I have read on the subject has recommended this a good practice.
The default behavior for filesystems set up by Red Hat tools (anaconda) is not to fsck. Not by mount count, nor by time. The default behavior for e2fsprogs was changed to disable periodic fsck in Feb 2011. CentOS 6 includes a version of e2fsprogs from before that change, but the filesystem is considered very stable, and the periodic fsck is not generally considered necessary.
I have confirmed that filesystems setup by anaconda on both CentOS 6 and RHEL 6 have both boot count and interval disabled however they are not disabled for any manually created filesystems (they are set to 24 and 6 months, respectively).
I find it interesting that as late as 2014 Red Hat is recommending:
. If automatic filesystem checks are inconvenient, then it is recommended to disable the automated filesystem check as discussed in the following article:
How to turn off forced/automatic fsck in Red Hat Enterprise Linux?
. Once disabled, it is recommended to schedule regular "human controlled/monitored" filsystem checks, when it is convenient to do so. These checks should not be ignored, or scheduled too far apart.
This is from https://access.redhat.com/solutions/70531
Regards, Hugh
On Tue, April 21, 2015 2:13 pm, Hugh E Cruickshank wrote:
From: Gordon Messmer Sent: April 21, 2015 10:30
On 04/21/2015 09:40 AM, Hugh E Cruickshank wrote:
I accept that fscks are required on a periodic basis and I
am willing
to reboot more often to achieve these but I would like to minimize downtime (during the reboot) where possible.
Why do you accept that?
Every article I have read on the subject has recommended this a good practice.
The default behavior for filesystems set up by Red Hat tools (anaconda) is not to fsck. Not by mount count, nor by time. The default behavior for e2fsprogs was changed to disable periodic fsck in Feb 2011. CentOS 6 includes a version of e2fsprogs from before that change, but the filesystem is considered very stable, and the periodic fsck is not generally considered necessary.
I have confirmed that filesystems setup by anaconda on both CentOS 6 and RHEL 6 have both boot count and interval disabled however they are not disabled for any manually created filesystems (they are set to 24 and 6 months, respectively).
I find it interesting that as late as 2014 Red Hat is recommending:
. If automatic filesystem checks are inconvenient, then it is recommended to disable the automated filesystem check as discussed in the following article:
How to turn off forced/automatic fsck in Red Hat Enterprise Linux?
. Once disabled, it is recommended to schedule regular "human controlled/monitored" filsystem checks, when it is convenient to do so. These checks should not be ignored, or scheduled too far apart.
Thus converting "Enterprise" into more or less home user system - for user with plenty of time to spare for manual system maintenance... ;-(
Valeri
This is from https://access.redhat.com/solutions/70531
Regards, Hugh
-- Hugh E Cruickshank, Forward Software, www.forward-software.com
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
On 04/21/2015 12:13 PM, Hugh E Cruickshank wrote:
From: Gordon Messmer Sent: April 21, 2015 10:30
Why do you accept that?
Every article I have read on the subject has recommended this a good practice.
Not every source is equal.
The maintainers turned that behavior off by default sometime around the release of RHEL 6 (before the release, but after the package set was finalized). Among at least any group I am aware of, ext had been considered very stable for quite a long time before that, and common practice was to disable periodic checks. (As Anaconda has since who-even-knows when. WAY back.)
I have confirmed that filesystems setup by anaconda on both CentOS 6 and RHEL 6 have both boot count and interval disabled however they are not disabled for any manually created filesystems (they are set to 24 and 6 months, respectively).
Right. Red Hat's policy was to disable the checks long before that default changed in e2fsprogs (in version 1.42).
. Once disabled, it is recommended to schedule regular "human controlled/monitored" filsystem checks, when it is convenient to do so. These checks should not be ignored, or scheduled too far apart.
CYA?
I'm not aware of such a recommendation in any of their publicly available documentation.
This is from https://access.redhat.com/solutions/70531
Can't access it, myself. My university has a site license for RHEL, but it doesn't give me access to the KB.
-
Gordon Messmer -
Hugh E Cruickshank -
Les Mikesell -
Valeri Galtsev