[PC-BSD Dev] Subject: Re: 9.0 Recommendation: partitioning

Kris Moore kris at pcbsd.org
Sun Sep 26 11:27:30 PDT 2010



"Roger Marquis" <marquis at roble.com> wrote:

>Andrei Kolu wrote:
>> In case of power failure during some write operations your filesystem
>> would be inconsistent, that means after restart your filesystem(s)
>> would be READ-ONLY. Now imagine that you got single / partition and
>> can't start fsck placed in /stand, you have to start your system from
>> livecd or something and hope that your partition scheme is not ruined.
>
>Journalling is a better protection against boot-time fsck.  At the very
>least ufs with soft-updates should be the default filesystem.
>
>But what Andrei is advocating here is a read-only root.  That is not the
>default now and, to the best of my knowledge nobody is seriously
>advocating that as a PC-BSD default.  To create a read-only root you'd
>need to partition at least /tmp, /usr, and /var, and that would create
>more issues than it would solve because:
>
>  * Every filesystem that has to be mounted at boot is a point-of-failure.
>
>  * Unless you also mounted /home you'd need to symlink /usr/home.  This
>    adds another one or two points-of-failure as well as the path issues
>    that to accompany directory symlinks.
>
>  * An unmountable /usr is worse than an an un-fsck'ed root partition
>    for all but the most experienced end-users.
>
>  * Every intra-disk partition reduces the free space of all remaining
>    partitions, and increases the risk of diskfull partitions.
>
>> Disk full trouble from servers of workstations? With single /
>> partition your system would be unusable if it is full but with
>> multiple partitions you are able to use it and at least delete some
>> files.
>
>Hasn't been my experience but then my systems have all used journalling
>filesystems for several years now.  Plus, anyone who knows how to login
>to a diskfull system with multi-intra-disk partitions probably also knows
>how to "mount -o rw /".
>
>> Also remember /usr partition  where /usr/home directory with
>> all users files are stored. Now recall quota feature. You don't want
>> to set quota for your system processes, do you? Quota is set by
>> partition.
>
>If you need quotas you need partitions no question, however, few
>end-users need quotas.  If you install non-journalling filesystems you
>may also benefit from partitions, at the expense of increasing the
>chances you'll experience inconsistent non-root filesystems.
>
>Bottom line, partitions within a disk create more points of failure than
>they eliminate.  This is statistics 101.  IMO, the defaults should
>reflect the fact that diskfull issues are more common than quotas and
>fsck issues for the average user.  The keywords here are "probability"
>and "average user".
>
>More importantly, and the bottom line for PC-BSD, end-users who
>experience diskfull problems due to unnecessary partitioning or fsck
>issues due to unjournalled filesystems are more likely to move to an OS
>with more intelligent defaults.
>
>IME,
>Roger Marquis
>_______________________________________________
>Dev mailing list
>Dev at lists.pcbsd.org
>http://lists.pcbsd.org/mailman/listinfo/dev


If you want the best of both worlds, just switch to zfs. Using it here, and my zpool uses all the disk space, and creating mount points is a snap. I don't need to worry about running out of room on / or /usr, plus I can treat them as separate partitions.  Or set compression and other options on the fly. :)


-- 
Kris Moore 
PC-BSD / iXsystems 


More information about the Dev mailing list