Tmpfs is Huge

Ghost Dawg · 2003-08-30 16:15:19

I was looking over my /etc/fstab and noticed that the tmpfs is over 2gb is size, why is it that big?

tmpfs /tmp tmpfs size=2G,nr_inodes=10k 0 0

With other distros, I never noticed it that big. I thought it is part of the root partition.

Thnx.

sarah31 · 2003-08-30 20:45:41

heh. mine is puny. far too small actually. it is about 256 or some dumb number like that which makes it very hard to download isos and such with web brwosers.

i think the size of tmp can be set in /etc/fstab

marin_linuxer · 2003-10-07 16:47:24

Alert to all Dev's:

I was just google'n on the 'tmpfs fstab' and I came across the post from a guy, whom I think added 'tmpfs' to the kernel, and he says:

[regarding the 'tmpfs' and mounting]
+3) Some people (including me) find it very convenient to mount it
+ e.g. on /tmp and /var/tmp and have a big swap partition. But be
+ aware: loop mounts of tmpfs files do not work due to the internal
+ design. So mkinitrd shipped by most distributions will fail with a
+ tmpfs /tmp.
+
+4) And probably a lot more I do not know about :-)
+
+
+tmpfs has a couple of mount options:
+
+size: The limit of allocated bytes for this tmpfs instance. The
+ default is half of your physical RAM without swap. If you
+ oversize your tmpfs instances the machine will deadlock
+ since the OOM handler will not be able to free that memory.
+nr_blocks: The same as size, but in blocks of PAGECACHE_SIZE.
+nr_inodes: The maximum number of inodes for this instance. The default
+ is half of the number of your physical RAM pages.
+
+These parameters accept a suffix k, m or g for kilo, mega and giga and
+can be changed on remount.
+
+The initial permissions of the root directory can be set with the
+mount option "mode". Later on you can change the permissions of the
+root directory with chmod.
+
+So 'mount -t tmpfs -o size=10G,nr_inodes=10k,mode=0700 tmpfs /mytmpfs'
+will give you tmpfs instance on /mytmpfs which can allocate 10GB
+RAM/SWAP in 10240 inodes and it is only accessible by root.
+
+
+TODOs:
+
+1) give the size option a percent semantic: If you give a mount option
+ size=50% the tmpfs instance should be able to grow to 50 percent of
+ RAM + swap. So the instance should adapt autatically if you add or
+ remove swap space.
+2) loop mounts: This is difficult since loop.c relies on the readpage
+ operation. This operation gets a page from the caller to be filled
+ with the content of the file at that position. But tmpfs always has
+ the page and thus cannot copy the content to the given page. So it
+ cannot provide this operation. The VM had to be changed seriously
+ to achieve this.
+3) Show the number of tmpfs RAM pages. (As shared?)
+
+
+Author:
+ Christoph Rohland <cr@sap.com>, 1.12.01

SOURCE POST:
http://groups.google.com/groups?q=autho … al&rnum=45

Am I to understand that we, in ArchLinux, _do_ or _don't do_ the part about:

+3) Some people (including me) find it very convenient to mount it
+ e.g. on /tmp and /var/tmp and have a big swap partition. But be
+ aware: loop mounts of tmpfs files do not work due to the internal
+ design. So mkinitrd shipped by most distributions will fail with a
+ tmpfs /tmp.

Just wondering. Thanx.

sarah31 · 2003-10-07 17:02:20

i, personally, do not like the allocation of 2GB of space to tmpfs so i just remove the size and nr_nodes parameter with "defaults". i may hinder myself a bit on occassion with this but when you have a few hard drives thyat have less than 6 GB on them it is not very desirable to lose 2GB to tmpfs

marin_linuxer · 2003-10-07 17:24:03

Sarah,

Yah, I just learned 'bout that when I was try'n to d/l an ISO and kept get'n 'out-of-space' errors. Is there any other way to get the kernel to use actual physical space to cache d/l's?

sarah31 · 2003-10-07 20:53:15

yeah use wget to download large files.

marin_linuxer · 2003-10-07 22:30:20

sarah31 wrote:

yeah use wget to download large files.

DOH! I forgot wget ... (brilliant little proggy). Thanx!

Jagged · 2003-10-08 04:11:48

i just remove tmpfs alltogether, and modify the shutdown scripts to cleanup the tmp dirs.

i do however maintain a tmpfs in /dev/shm in case i need it for something... but its set at default (4096K). tmpfs has the ability to grow dynamically

Arch Linux

#1 2003-08-30 16:15:19

Tmpfs is Huge

#2 2003-08-30 20:45:41

Re: Tmpfs is Huge

#3 2003-10-07 16:47:24

Re: Tmpfs is Huge

#4 2003-10-07 17:02:20

Re: Tmpfs is Huge

#5 2003-10-07 17:24:03

Re: Tmpfs is Huge

#6 2003-10-07 20:53:15

Re: Tmpfs is Huge

#7 2003-10-07 22:30:20

Re: Tmpfs is Huge

#8 2003-10-08 04:11:48

Re: Tmpfs is Huge

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