Partitions and File Systems

COMMUNISTCHINA · 2008-08-15 04:58:58

So, if you make a / partition and a /home partition, how does your /home directory know to be in the partition instead?

Acecero · 2008-08-15 05:14:34

COMMUNISTCHINA wrote:

So, if you make a / partition and a /home partition, how does your /home directory know to be in the partition instead?

Because linux owns like that... No I'll be more specific, its because you set a certain partition to be mounted to a certain directory in fstab so it knows which partitions for each directory to occupy at bootup.

new2arch · 2008-08-15 07:03:20

Garns wrote:

Depending on how much packages you install, you should give var a bit more space. I'm not really happy with just 2GB, Im filling the partition much too often.
This is basically my fault, because I clear up my cache very seldom and tend to download monsters like KDE4 just to look at it...
However I would recommend at least 3GB for var, probably more.

Yeah, /var tends to grow out of proportion. Perhaps 5 gig or more would suffice if you don't want to clean uninstalled packages from your system once in a while? I tend to clean my pacman cache when the size exceeds 1.5 gb.

Vintendo · 2008-08-15 16:12:37

I am going to reinstall arch, went for XFS for / (and /var) last time. Bad(!) choice, So i am thinking this:

Mount point Size Filesystem
/: 10 Gb ?
/boot: 100 Mb Ext2
/var: 5Gb ReiserFS
/home: The rest ? (resizable(including shrinking) and journaled)

Does anyone have advice for me?

patroclo7 · 2008-08-15 16:20:50

Reiserfs for /var is nice (pacman goes faster, and those who would like it working with a database instead that with the filesystem are force to shut up ), a dir_indexed ext3 for /home seems to fulfil all your needs.

Vintendo · 2008-08-15 16:23:14

I was thinking about ext3 so that was a nice choice:) What do you recommend for /, en what do you think about sizes?

Another question, I have 3 hard drives. Currently i have two entire drives and one partition in an lvm setup. Root isn't in lvm yet, i am not shure if i should do so. What do you say?

Last edited by Vintendo (2008-08-15 16:38:19)

patroclo7 · 2008-08-15 16:39:43

I use ext3 also for / (in general you should consider to dir_index it with tune2fs). I have a 10GB /, a 7GB /var and all the rest for /home.
I do not think that reiserfs is going to give great benefits outside /var (the manipulation of small files actually happen there), so I would not consider it for / due to the long mount times at boot. I have had terrible problems with jfs in the past, may be that now they are solved, but I am still too shocked to go back to it. xfs is specialized for large files, so I would consider it only for /home, but I dislike the fact that it is not possible to shrink it.

In general, ext3 dir_indexed seems to me the best general purpose filesystem, with the exclusive exception of /var (in particular due to pacman).

fukawi2 · 2008-08-16 00:00:49

Every person is going to do it differently (as you can see )

Personally, for a 'server', I would do something like this:

/boot    32mb    ext3     (I never keep multiple / custom kernels so don't need heaps of space)
/        10gb    JFS        
/var     4gb     JFS      (if something like logging or mail goes haywire and 'spams' the disk, /var can be filled without stuffing up the rest of the system)
/tmp     4gb     JFS      (mount with noexec etc options. _Helps_ prevent users from filling / partition and stuffing things)
/usr     12gb    JFS      (mount read-only. Helps prevent unauthorized changes to /usr/bin/ and /usr/local/ etc)
/srv     ??gb    JFS      (something I picked up from Ubuntu - if I want to serve things like Apache or Samba etc, I can place the files they use here)
/home    *gb     JFS
swap     2 x RAM

Last edited by fukawi2 (2008-08-16 00:02:16)

iBertus · 2008-08-16 03:40:11

COMMUNISTCHINA wrote:

So, if you make a / partition and a /home partition, how does your /home directory know to be in the partition instead?

You'll have to place an entry in the fstab file during setup to ensure the initscripts mount the partition to /home before anything is written to the location.

Something like:

/dev/sda2 /home reiser4 defaults,nodev,nosuid,noatime 0 2

Does anyone use Reiser4? I don't, just used it in my example.

Last edited by iBertus (2008-08-16 03:41:37)

new2arch · 2008-08-16 08:08:20

iBertus wrote:

COMMUNISTCHINA wrote:
So, if you make a / partition and a /home partition, how does your /home directory know to be in the partition instead?
You'll have to place an entry in the fstab file during setup to ensure the initscripts mount the partition to /home before anything is written to the location.
Something like:
/dev/sda2 /home reiser4 defaults,nodev,nosuid,noatime 0 2
Does anyone use Reiser4? I don't, just used it in my example.

I've never had to add any specific entry to my fstab file during the installation to make sure the scripts will recognize /home as a separate partition. It has always been done automatically.

patroclo7 · 2008-08-16 11:31:20

new2arch wrote:

I've never had to add any specific entry to my fstab file during the installation to make sure the scripts will recognize /home as a separate partition. It has always been done automatically.

You are lucky, I remember a couple of case where this was necessary, anyway it is better to check fstab: if nothing needs modifications, so far so good.
Anyway if you need custom mount options you need to add them there.

new2arch · 2008-08-16 18:56:31

patroclo7 wrote:

new2arch wrote:
I've never had to add any specific entry to my fstab file during the installation to make sure the scripts will recognize /home as a separate partition. It has always been done automatically.
You are lucky, I remember a couple of case where this was necessary, anyway it is better to check fstab: if nothing needs modifications, so far so good.
Anyway if you need custom mount options you need to add them there.

Weird. I thought the necessary configurations were automagically made and then added to fstab when you partition the disk and mount the partitions. In Archlinux, Fedora, Zenwalk CentOS, OpenBSD, PCLinuxOS - the entries in fstab were always there when checking them out after the virgin boot. And yes, I tend to double check in Nautilus /Thunar to make sure the partitions are being mounted correctly. I must be a very lucky man. :-D

Last edited by new2arch (2008-08-16 18:57:54)

patroclo7 · 2008-08-16 19:10:57

new2arch: actually this should not be necessary in any of the distros you mentioned, so your luck consists in having found them bug-free. But: in arch in the past the installer was not so precise on this point; in distros such as CRUX the need to write by hand your fstab is seen as a feature

new2arch · 2008-08-16 19:43:22

patroclo7 wrote:

new2arch: actually this should not be necessary in any of the distros you mentioned, so your luck consists in having found them bug-free. But: in arch in the past the installer was not so precise on this point; in distros such as CRUX the need to write by hand your fstab is seen as a feature

Thanks for the explanation. I guess Archlinux and other modern distros are way more automated than I thought (compared to CRUX et al). I know I'd hate to manually mess around with fstab for making 6-7 partitions work!

Barrucadu · 2008-08-16 19:49:33

Editing the fstab isn't too hard - I change around my partitions so often I've more or less written it all from scratch anyway.

new2arch · 2008-08-16 19:52:12

Barrucadu wrote:

Editing the fstab isn't too hard - I change around my partitions so often I've more or less written it all from scratch anyway.

I feel like I'm hijacking the thread, but why would you want to change around your partitions?

Barrucadu · 2008-08-17 12:00:50

Well, I started with four (/boot, , swap, /, /home), have since added an extended partition, recreated /home as a logical partition, added /var as a logical partition, and added another logical partition to hold Qemu hard disk images.

DaveCode · 2008-09-09 12:14:53

Here is an fstab that is running Arch Linux like a rock since I got started with Arch. Keep in mind this is a DESKTOP. But it can also work as a server with attention paid to your specific server-related needs.

# ==========================================================
# ==========================================================
# fstab for 2 GiB RAM DESKTOP system
# no swap! no logs on disk!
# = FAST!
# = SAFE! (from power crashes and/or fs corruptions)

none /dev/pts devpts defaults 0 0
none /dev/shm tmpfs defaults 0 0
/dev/cdrom /media/cdrom auto ro,user,noauto,unhide 0 0
/dev/dvd /media/dvd auto ro,user,noauto,unhide 0 0

# RAM stuff ================================================

tmpfs /tmp tmpfs rw,nosuid,noexec,noatime,
size=50M,nr_inodes=2k 0 0

tmpfs /var/log tmpfs defaults,noatime,size=5M 0 0

tmpfs /var/run tmpfs defaults,noatime,size=5M 0 0

tmpfs /var/lock tmpfs defaults,noatime,size=2M 0 0

# optional,
tmpfs /mnt/ramdisk tmpfs rw,nosuid,noexec,noatime,
size=150M,nr_inodes=4k 0 0

# DISK stuff ===============================================

# BOOT
# ~ 1 GiB or less (ok ok, smaller yes, but I boot N kernels)
UUID=xx...xc /boot xfs noatime,nodiratime,async,barrier,
rw,dev,suid,exec,auto 0 1

# ROOT
# ~ 10-20 GiB
UUID=xx...xa / xfs noatime,nodiratime,async,barrier,
rw,dev,suid,exec,auto 0 1

# HOME (plus usr/local, see below)
# ~ 10 GiB and up, depending on user count,
# media files, disk capacity, etc
UUID=xx...xb /home xfs noatime,nodiratime,async,barrier,
rw,dev,suid,exec,auto 0 1
# ==========================================================
# ==========================================================

Linux suffers from the server legacy of Unix. My own practice is to strip that garbage out. Don't even get me started on ext3 and ext4, "new and improved" with extents...just like XFS. Just use XFS or JFS. People who badmouth XFS are full of it. We've lost tons of data to ext3 and I can't stand it, even when ext4 starts imitating XFS, they still badmouth XFS.

mkfs.xfs -s size=512 -b size=2048 -d agcount=8 -i attr=2,maxpct=5,size=512 -l internal=1,version=2,lazy-count=1 -n version=2 -L <diskname> /dev/sd<N>

then if you need it, set the UUID:

xfs_admin -U xxxxx

which is retrieved by

/lib/udev/vol_id --uuid /dev/sd<N>

As you can guess, I turn off logrotate cron jobs. Matter of fact, I turn off cron itself. Yeah I know, bad practice. Sure, if you're a headless server. If you're not, it's fine. All I do is "updatedb" by hand once in a while.

Let me tell you about bad practice ... cron jobs that in the middle of a system crash from some app, try to email root about it, and hang the whole system. Or when things are working, and I'm deeply concentrating on some task, decide it's time to eat my CPU cycles right when I need them.

Sysadmins develop bad attitudes after a while, you see...:-)

Now avoiding swap is an uncommon move. You may need it for suspend hibernate and such but that is a laptop problem as far as I'm concerned. The number of system users may also make some input here.

Finally, this is just me, I symlink /usr/local to a folder on HOME partition.

mkdir /home/usrlocal
cd /usr
ln -s -f /home/usrlocal local

That way if I change the Linux OS, reinstall or whatever, I retain the custom stuff with an easy symlink operation. This is basically where my custom scripts and apps go. (I don't use /opt.) So far so good with Arch this way. When I want an app that is out of date in Arch repos, I build it from source with --prefix=/usr/local and all's well. Just have /usr/local/bin and /usr/local/sbin on your shell $PATH. Even man pages work fine from /usr/local/man.

I might just have a separate partition for /usr/local. The symlink method is a poor-man's LVM without the LVM hassle. Either /home or /usr/local can eat up whatever space exists. You have plenty to spare.

The "filling of /var" shouldn't happen, in general. Poke around if it gets big and clean house by hand. Technically all those files are supposed to be volatile. If they are not, voila, you have discovered brain-deadness in Unix design.

My best success has come from un-thinking Unix fathers and saving the OS from itself.

You had better edit your fstab! No matter what installers do, you want to have noatime on every file system type, unless you *really do* want to know access times for some reason. Every one of them is a write-to-disk and hence a performance killer.

fukawi2 · 2008-09-09 22:11:12

Wow - who knew that so many people have gotten it wrong over the years

Thanks for sharing though - there's some good, and some interesting, points in there.

haxit · 2008-09-09 22:38:49

Not to hijack, but how does this sound:

/: 20gb: ext3
/boot: 100mb: ext2
/home: 5gb: ext3
/docs: rest: ext3
swap: 4gb (I don't know why )

BåGan · 2008-09-10 15:38:48

I'm converting to Arch as my main OS within a few weeks. So I'll lend this thread for a question

I'll use Arch for everything else than games and video editing that I will be using Vista(:() for.
I got a 190 gig harddisk on my lappie that I can use.

As for the file system, I would like the most stable first and foremost, and fast filesystem.
So my question to you fine people, how should I set this up? I see many partitions I dont even know what is in this thread Do I need /boot for exampel?

This is what I've been thinking:

/ - 15 gb (Enough for root?) (File system?)
/home - 20 gb (I want to encrypt this partition) (File system?)
/swap - 3 gb (Is this needed? Recommended?) (File system?)
/Vista - 15 gb (Enough for Vista?) (NTFS)
/Rest - 137 gb (Thinking of NTFS on this, mainly because of video editing. Any downside for using NTFS in Linux/Arch?)

Thanks in advance if anyone cares to respond

Cosay · 2008-09-10 17:32:32

BaGan,

The /boot partition it is a convention that many Linux distributions seem to use these days, so I use it too, but if you wanted to you could get by with just three partitions: Vista, /, and Swap.

In regards to Vista, Microsoft recommends a 20 GB hard disk for Home Basic and 40GB for the other versions. I personally would recommend following that when partitioning, since Vista can be a diskspace hog (not to mention that the video editing you do must use up some disk space).

I think most people would agree that Ext3 is considered to be the safest journaling file system for Linux because of its widespread use and adoption.

Last edited by Cosay (2008-09-10 17:32:59)

fukawi2 · 2008-09-11 00:25:56

ext3 is probably the safest file system to use, depending who you talk to. Having said that, most file systems are mature and stable enough these days. I personally moved from ext3 to JFS 12 months ago and love it.

As for your /rest partition, if you want to share the partition between Windows and Linux, I'd suggest using FAT file system which is better supported under Linux than NTFS. There is good read support for NTFS, however writing can still be touch and go.

15gb for / should be ample.
3gb swap should be fine.
I'm not sure about Vista since I've only ever used it for 15 minutes ( ) - but 15gb seems a bit low.

curve · 2008-09-11 00:49:08

fukawi2 wrote:

As for your /rest partition, if you want to share the partition between Windows and Linux, I'd suggest using FAT file system which is better supported under Linux than NTFS.

I was always told that vfat was unreliable past 16GB.. maybe someone here can confirm/deny that.

Personally I have my XP split into 15GB system and 450GB data, and I just share that ntfs data partition (music, docs, downloads, pics, videos, etc.) with my arch install.. no issues writing to it with the ntfs-3g driver as of yet.

fukawi2 · 2008-09-11 02:10:19

curve wrote:

I was always told that vfat was unreliable past 16GB.. maybe someone here can confirm/deny that.

I haven't heard that... I use vfat on all my external media (ie, USB hard drives) including my 120gb Seagate FreeAgent with ALL "my documents" on it, and my 160gb SATA (in caddy) that I use for transferring music / videos etc between friends... These drives go between Windows and Linux (and sometimes Mac) and all works perfectly

Using vfat just makes it easier IMHO - especially when I plug in to a Linux machine that doesn't have ntfs-3g

EDIT:
http://support.microsoft.com/kb/314463

The maximum disk size is approximately 8 terabytes when you take into account the following variables: The maximum possible number of clusters on a FAT32 volume is 268,435,445, and there is a maximum of 32 KB per cluster, along with the space required for the file allocation table (FAT).

http://en.wikipedia.org/wiki/File_Allocation_Table also supports that statement

Last edited by fukawi2 (2008-09-11 02:13:37)

Arch Linux

#26 2008-08-15 04:58:58

Re: Partitions and File Systems

#27 2008-08-15 05:14:34

Re: Partitions and File Systems

#28 2008-08-15 07:03:20

Re: Partitions and File Systems

#29 2008-08-15 16:12:37

Re: Partitions and File Systems

#30 2008-08-15 16:20:50

Re: Partitions and File Systems

#31 2008-08-15 16:23:14

Re: Partitions and File Systems

#32 2008-08-15 16:39:43

Re: Partitions and File Systems

#33 2008-08-16 00:00:49

Re: Partitions and File Systems

#34 2008-08-16 03:40:11

Re: Partitions and File Systems

#35 2008-08-16 08:08:20

Re: Partitions and File Systems

#36 2008-08-16 11:31:20

Re: Partitions and File Systems

#37 2008-08-16 18:56:31

Re: Partitions and File Systems

#38 2008-08-16 19:10:57

Re: Partitions and File Systems

#39 2008-08-16 19:43:22

Re: Partitions and File Systems

#40 2008-08-16 19:49:33

Re: Partitions and File Systems

#41 2008-08-16 19:52:12

Re: Partitions and File Systems

#42 2008-08-17 12:00:50

Re: Partitions and File Systems

#43 2008-09-09 12:14:53

Re: Partitions and File Systems

#44 2008-09-09 22:11:12

Re: Partitions and File Systems

#45 2008-09-09 22:38:49

Re: Partitions and File Systems

#46 2008-09-10 15:38:48

Re: Partitions and File Systems

#47 2008-09-10 17:32:32

Re: Partitions and File Systems

#48 2008-09-11 00:25:56

Re: Partitions and File Systems

#49 2008-09-11 00:49:08

Re: Partitions and File Systems

#50 2008-09-11 02:10:19

Re: Partitions and File Systems

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