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desbyleo 04-08-2003 06:17 PM

Defining the Slices
I'm very familar with working with SUN/Unix. However, I'd like to know more on the system administration side of it.

For starters, I'd like to get some tip on how to best define slices on my to split the various slices apart the best way. I've heard some say to lay it out this way:

/ (128MB) Slice0
/usr (2GB) Slice3
/var (1.5GB) Slice4
/opt (1.5GB) Slice5

and putting /export/home on a totally separate disk.

What's your take on that??

trickykid 04-11-2003 11:46 AM

Defining your slices on a machine or server really all depends on your preferences, what the machine will be used for.. etc.

Even with the home directory on a different server can benefit but that all depends on how your setting it up and if you can on your existing network.

Basically a standard Solaris install consists of maybe:

swap = 200 MB
/ = minimum of 300 MB
/usr = minimum of 800 MB or so.. but you'll usually want more cause this is where most programs reside..

But you should get the idea though.. it all really just comes down to how you use the machine, who is using it and go from there.

stickman 04-11-2003 07:28 PM

The installation process does give you minimums and recommended for each slice. The exact slice sizes are determined by what you want to use the box for and what you are going to install. For example, a firewall would typically need a larger than average /var for log space. You need to know your applications.

desbyleo 04-16-2003 11:59 AM

I gues your replies seem fair enough. Although I guess my problem is...being too new to the environment, I may not know the what each directory is typically used for. For example, so far I know that /var is typically for log files (files that tend to get that info I need to put in consideration); the /usr is typically used for application installation (also may need more space). But still there's others like /etc and /opt. I also heard that /opt is typically where you put third party application (would then be different from /usr applications?)

Anyhow, perhaps y'all can break out the different directories and give a brief info on what those directories are typically used for.

I also heard that gone are the days where SA even bother breaking out some of the directories into there own file system since disks are becoming so big and so rick of running out of room for the OS ("/" file system). IS that true in day to day practices?

Perhaps y'all can indulge in a bit of retoric about this I can aasume y'all have your own way of looking at this subject.


trickykid 04-16-2003 12:21 PM

Directories and what they are used for in a *nix type system:

/ - root directory, all directories reside under root.
swap - swap space
/home - user's home directories
/etc - where configuration files are stored
/usr - where programs and most common commands are stored, library files can also be stored here.
/lib - library files are stored here
/opt - where other applications are stored, stands for optional
/tmp - temporary files are stored
/var - log files reside here
/dev - device directory, its a pseudo file system
/proc - this is a directory for processes, another psuedo file system
/sbin - where more commands are stored, usually only root has access to these
/root - root's home directory
/bin - other system type commands are stored
/boot - boot files are stored here

I think that about covers the most common directories.. anyone else want to throw some in? :)

desbyleo 04-16-2003 02:59 PM

Yeah...would appreciate it if anyone else had anymore to add. What would be valuable is to include certain considerations to take for any/all of the above directories.

For example, someon had already said that since log files reside in /var, consideration to take in is that that can have the potential to grow and eat space keep it away from / or make sure you have plenty of space.

Any consideration to keep in mind (for a newbie to *nix) for the other directories?

trickykid 04-16-2003 03:10 PM


Originally posted by desbyleo
For example, someon had already said that since log files reside in /var, consideration to take in is that that can have the potential to grow and eat space keep it away from / or make sure you have plenty of space.

Any consideration to keep in mind (for a newbie to *nix) for the other directories?

Well basically your /var and /tmp directories have the potential to get larger as more logs, temp files are being used. They don't necessarily need to be large but its always a good idea to make them have their own partition. Cause if for some reason they reside on the same partition as /, and something happens to fill up your logs taking up all the available space, then your system won't boot up cause there's not space left.. causing a big mess. If you have them on their own partition, you'll still be able to boot with much more ease, to go in and clear them out to make more space on their own partitions.

I usually make my /tmp and /var partitions between 500MB and 1GB, depending on the size of the hard drive, if its a server or desktop.. etc.

desbyleo 04-16-2003 03:14 PM

Sweet...thanks Trick. See that's good stuff you won't get (or remember) from reading or know to ask in training. But now that I've made this effect, I'll have that much more of common sense.

This is good stuff...keep'em coming.

jdc2048 04-21-2003 07:54 PM

the three partitions that you will absolutely have to have in order to boot the O/S are "/, /var, & /usr". The "/" is obvious, the "/var" is necessary because the system must be able to write to the tmpx & wtmpx data files (contain system login log information, you will not be able to login even in single user without these). The /usr partition generally contains many of the systems executables (aren't /bin & /sbin just symlinks to /usr/bin & /usr/sbin ?). There is also kernel information contained in /usr/kernel.

You could technically merge everything into 1 filesystem, but I personally don't recommend it. There are many things to consider in regards to this. The first thing that comes to mind is backup/restore. If you merge everything, then _everything_ will have to be backed up and subsequently restored. When you partition, you can backup only those partitions that change often (/home & /var) on a daily basis, then perform a full system backup once a week/month depending on the value of your data.

When you go to restore a missing file or directory (or filesystem), you will have less data to sift through with a partitioned HD. For instance, you will only be looking through a 800 MB "/usr" partition instead of a 2+ GB "/" partition.

Partitioning could also give you other benefits such as mirroring the critical "/, /usr, /var" partitions onto a second disk, without adding the overhead of mirroring everyones home directories (less critical)

fancypiper 04-21-2003 08:25 PM

I don't run Solaris, but there is a good O'Reilly article about the Linux filesystem layout: Proper Filesystem Layout

Perhaps that would help.

desbyleo 05-07-2003 09:18 AM

Good stuff! Thanks! I love this forum.

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