Filesystem sizes

[dictum9]

Building a new system with 11.23 on PA-RISC, just wanted to know opinions on the partition sizes I choose. I know the sizes highly depend on what the box will be used for.
I wonder if I should increase swap.

============================================
name type size % used VG
============================================
/stand VxFS 512 5 vg00
primary SWAP+D 4096 0 vg00
/ VxFS 1024 43 vg00
/home VxFS 752 0 vg00
/opt VxFS 4608 53 vg00
/tmp VxFS 3072 0 vg00
/usr VxFS 4504 63 vg00
/var VxFS 6144 29 vg00

[Jonathan Fife · Accepted solution]

I use a general guideline of making swap 2x physical memory.

[James R. Ferguson]

Hi:

Filesystem sizes depend on the Operating Environment you load along with addtional software you might add. This applies particulary to '/usr' and '/opt'.

Too, the sizes "necessary" for '/var' (particularly) and to a lesser extent for '/tmp', are heavily influenced by patch activities; the cleanup cycle you do for the IPD (Installed Product Database --- '/var/adm/sw') and things like printing.

The installatino guide offers some basic suggestions:

http://docs.hp.com/en/5991-4794/ch02s02.html

Regards!

...JRF...

[Arunvijai_4]

Hi ETC,

Always go with the rule of thumb, swap = 2* size of real memory.

Also, look at this thread : http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=94936

-Arun

[DCE]

Overall not too bad in my opinion

Do you have extra space on the root disk?

If so, look at your % used - /opt and /usr might benefit from and increase in size.

Also - one of HP's quirks /var is patch records go - if you plan to keep the system a while, make sure there is enough room for all the future patches!

[Deoncia Grayson_1]

My initial question would be how much memory do you have on the server before suggesting you go for twice that in swap...

Also the sizing looks fine but how much space do you have left in the root volume group?? If you needed to, can you increase the filesystems size?


Deoncia

[dictum9]

I saw the HP filesystem table... 212 MB for /tmp? They have got to be kidding. I used to set it to 2GB and even that's not enough often enough.

I imagine the table is based on really small disk size, like 4GB.

[dictum9]

Yeah, I have about 4GB left. I am thinking I will leave that for future possibilities.

Memory is 5GB and I made swap twice that...

[Paul F. Carlson]

Jonathan and Arun,

Out of curiosity: why do you set up your swap as 2x physical memory? What is your reasoning?

Paul

[A. Clay Stephenson]

saw the HP filesystem table... 212 MB for /tmp? They have got to be kidding. I used to set it to 2GB and even that's not enough often enough.


Wrong, wrong, wrong

/tmp should be quite small (200-500MiB) because /tmp is ONLY to be used for OS related scrathpad files; user related scratchpad files go in /var/tmp unless overriden to still another location by setting TMPDIR. The only time /tmp needs to be larger than your current value is if there is some idiotic code that uses /tmp and even then the solution should be to modify the code to use /var/tmp. By having a large /tmp, you are really acting as an idiocy enabler.


The one filesystem that really looks too large is /. It need be no larger than about 256 MiB and that is quite generous.

Swap should be as big as you need and no more. That's really the rule. What I typically do for systems with large amounts of memory is configure 512Mib-1GiB of primary swap (you must have some) and then add additional swap to bring me up to 25% of memory. You then monitor swap usage and add additional swap space as needed. It's so easy to add additional swap as long as you leave some room on the VG's that it is not worth worrying about.

[Bill Hassell]

Just a comment about /tmp. For the V.4 filesystem layout definition, /tmp is for OS use only. Unfortunately, a LOT of aging code misuses /tmp and larger sizes are the result (rather than fixing the old code). The correct directory for user and application code is /var/tmp. A couple of variables that are often not set are TMPDIR and TEMP -- put them in /etc/profile and application scripts:

export TEMP=/var/tmp
export TMPDIR=/var/tmp

[dictum9]

Are you saying I should make /tmp smaller and give more space to /var?

[dictum9]

Another question, does /tmp clear on reboot and /var/tmp doesn't?

[Sean Dale]

/tmp on our systems is only 1 gig, and it's about 30% full at any given time. I, too, would suggest you make /tmp a little smaller and add space to /var.

[A. Clay Stephenson]

Both of us are saying that regardless of the size of /var/tmp, /tmp is large by today's standards and something around 200MiB or so should be sufficient. Best practices generally have a relatively small /var filesystem be have separate filesystems mounted under it such as /var/tmp, /var/spool, /var/mail, /var/opt/omni, ... . If /var fills up, bad things will happen to your system (read it will become VERY unresponsive) so by dividingvar into more manageable chunks, you lessen the risk.

Whether or /tmp and/or /var/tmp are cleaned up depends upon how the clean_tmps rc script is configured. Generally, it just cleans /tmp but reboots are so infrequent that cleaning temporary directories should really be done by a cronjob (and a well-written one at that).

[James R. Ferguson]

Hi (again):

Automatically clearing (removing files) in '/tmp' is controlled by the startup script '/sbin/init.d/clean_tmps'.

Setting CLEAR_TMP=1 in 'etc/rc.config.d/clean_tmps' arms the cleaning.

Regards!

...JRF...