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Re: Re[4]: disk partition schemes

On Friday 22 June 2001 17:33, Kevin J. Menard, Jr. wrote:
> RC> What exactly will that save you from?  If the root FS gets messed
> up then RC> having a separate /boot won't gain you much...
> I was thinking the other way around actually.  If /boot were to get
> messed up, it wouldn't affect /.

As /boot almost never gets written to I think it's the least likely 
partition to get seriously stuffed.

> Well, I'll be using Cyrus IMAPd.  Doesn't use Maildir, but does create
> separate folders per user.  Thus, the spool is really not going to hold
> data much. However long it takes to rip data off incoming (using
> postfix) and send it out, or however long to hand it off to lmtpd and
> let cyrus deliver it.

OK.  So you want Cyrus storage on the file system used for user data.

> RC> If you have two partitions on the same physical media (in this case
> a RC> RAID-10) then expect to lose performance.  If you make it all one
> large RC> partition then the file system drivers can optimise things
> more.
> Oh.  Guess I didn't quite understand how disk I/O functioned.  I
> figured something like /var, which will have a lot of synchronous
> writes, would get better performance outside of / or /home.

IFF you have separate physical hardware for the different file systems 
that will be true.  However you only have one physical device (the RAID 
device) so this will not be a benefit.

> RC> I recommend having a separate /home to limit the things that can go
> RC> wrong.  I recommend leaving /var on the root file system unless you
> need RC> a lot of space in /var.
> Just from a performance point of view or for other reasons?

Having /home and /tmp on separate devices to / gives some security 
benefits by limiting the ability to produce hard links.  Hard linking 
/etc/passwd or /etc/shadow to a name under /tmp or the user's home 
directory has been step 1 of a number of security attacks...

Having /tmp and /home on separate devices to the root FS limits the 
ability of hostile users to perform such attacks.

> RC> Also consider a separate file system for
> RC> /var/tmp and make /tmp a sym-linke to /var/tmp/tmp .
> Once again . . . just for stability?  security?

Security as described above and stability regarding issues of lack of 
space and/or Inodes.

> >> drives have come a long way, and with a RAID 10, would I be safe in
> >> doing this?  Or should I just have a coulple gig / and the rest for
> >> /home?
> RC> RAID has no relevance to the issue of partitioning in this sense.
> Well, my point here was, with the RAID 10, I already have a pretty good
> amount of reliability, as if one drive fails, the system can still
> function.  And with disks that are pretty reliable to begin with, I
> wasn't sure if the combination of all these would merit just one large
> / fs.

How will one partition or two partitions affect reliability?  Disk 
failures tend to be boolean things, if a disk starts dieing then all data 
seems to rapidly disappear from it.  So in you don't have RAID then 
having separate partitions is unlikely to save you.

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