SUMMARY: solaris filesystem recommendations

From: Maddox, Andrew <>
Date: Thu Jun 06 2002 - 09:48:10 EDT
Hash: SHA1

My thanks to all who replied, a few too many respondents to list (20
people so far, and still coming in), so on with the summarizing:

The general consensus is "keep doing pretty much what you have been

A few people do go with one big / partition, but not generally for
servers. With the large size of disks these days, most people agreed
that the risk of partitions filling up and hanging a system is pretty
remote, except for some things like /var, /export/home if users will
have accounts on the system, and sometimes /opt. Solaris apparently
likes to treat / and /usr as one thing now, and since those do both
need to be available for single-user mode and in disaster recovery,
it makes sense to put them into one big partition.

In my case, I've decided to go with this as a base config, since I've
got 36GB disks in the current systems, but only 2 disks on some of
the machines (so I need to keep one free for at least a simple
/ - 6GB
swap - == physical RAM, since the servers all have at least 2GB.
2xRAM would be overkill
/var - 2GB to separate logging and spooling. /opt/var and /usr/var
will probably end up as links to this
/tmp - 2GB of real space, because I've had too many problems in the
past with developers writing apps that log *everything* to /tmp, and
end up eating up all of a Sun's swap and killing the box.
/export/home - probably 4 to 8 GB

Then, additional filesystems for application code, databases, and the
like will be created and sized as needed.

A few people recommended using Solstice DiskSuite for the RAIDing,
which I was wondering about. It seems to have matured quite a bit
since I last used it, so I'll probably try it out rather than trying
to get funding for something else.

Selected quotes and notes follow: highly recommended "Boot Disk Management" by
John S. Howard and David Deeths as a reference

Thanks to, who pointed me to the Sun
documentation at,
which has some good info available. He also summarized things nicely
with "I suggest you have a separate filesystem for the stable and
important bits of the system (/, including /usr), a nice big one for
/var, and separate
any application and data filesystems which are likely to change as
the system grows (/usr/local, /opt, etc.)." says:
"The truly paranoid sysadmins still put /var and /usr on separate
partitions, especially on mail servers, so that / remains relatively
static. There is nothing worse than coming to work on Monday morning
and finding / full because a weekend SPAM attack filled up the logs
or a network outage backed up the mail spool."
but reminds me: "Don't forget: along with bigger disks comes bigger
network pipes, so things go wrong even faster."
and "Of course, in real life, we usually inherit systems built and
spec'd by someone else, so rarely do we get something we can
configure and install from scratch." echoes my feelings: "Use your old rules..."Put
everything in a big /" is still idiotic for all the same reasons it
used to be."

A good, longer note from

"We put 4 partitions on the root disk:  /, /var, swap, metadb info.
The metadb info is < 2 MB in size and used for DiskSuite (see next
paragraph).  Swap is 1-4 GB in size, depending on how much RAM is in
server.  /var is also 1-4 GB in size, depending on what the server's
/ is the rest.

We set it up this way because it makes it simple to mirror the root
disk with DiskSuite - just 3 partitions to mirror.  I consider
the root disk essential.  I prefer DiskSuite to Veritas for mirroring
root disk because it is both simpler to set up and easier to recover
in the
event of a disk failure."

- -- 
Andrew Maddox, UNIX Systems Engineer
US Enrichment Corporation/CAI - 301.564.3360 -

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Received on Thu Jun 6 09:53:19 2002

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