Suggestions and ideas about filesystem sizing on Solaris
For
/ (root) filesystem normally you do not need so much disk space. Most
of the time you can allocate 256 MB or ever less, but 512 MB is one
very good value. Do not tempt to allocate big amount of space and put
all directories as /, usr, var, opt, export/home in one filesystem.
This can look very sample, but can put you in trouble after some time.
For
/usr filesystem you need average 2048 MB. On time of installation,
installer will show you how much you need. Don't put much more space
ever if you think to install big amount of software in /usr/local. If
this happen, just create separate filesystem.
For virtual memory i suggest to use this schema:
< 1 GB – RAMx2.5
<2 GB – RAMx2
<4 GB – RAMx1,5
>4 GB – RAMx1
Here
you should get above just as starting point, because many applications
have own requirements. For example Oracle+SAP need swap to be four
times RAM, almost independently of size of real memory, but Oracle
itself (if it's alone) “prefer to live” in RAM.
For /var
filesystem you can allocate as minimum 512 MB, but if you expect big
log files – from system, applications, etc, you should allocate
more. Do not forget log rotate utilities, they can help you save some
disk space. If your server will be used for jobs, generating big amount
of data in /var as mail server or print server you can allocate more
disk space, but because most of the print and mail software use
/var/spool you can create dedicated filesystem for this purpose.
Normaly
/tmp filesystem is “part” of swap, but for some products as
Oracle you can set dedicated filesystem. Normally 512 megabytes are
enough.
For /opt filesystem you should decide the size by self,
because in this filesystem normally in Solaris are located
installations of external software. 256 MB should be enough for many
purposes, but some software (Oracle by example) can fill more that 1.5
GB only for executable files.
And last but not least /export/home.
Do not set this filesystem very big. Later if it's need you can move
home directories and files to new filesystem or create new one like
/export/home2 for new users
And do not allocated entire disk
ever if you use some volume manager because later when you need
diskspace for new filesystem of extend existing one can be hard to get
new harddisk