Hello,
I am setting chrooted environments with Centos/Fedora Core distros recently. packages are installed in the chrooted environment without problems.
Then when it comes to /proc and /sys 'virtual'(not real hardware) file systems I got confused -- some documents say I should run 'mount -t proc none /proc; mount -t sysfs none /sys' to mount /proc and /sys, while some others say commands 'mount -t proc proc /proc; mount -t sysfs sysfs /sys' instead. I don't know what is the difference between the source device name 'none' against 'proc' and 'sysfs'. Any one can shed a light onto this?
In fact, I tried command 'mount -t proc kidding /proc; mount -t sysfs kiddingAgain /sys' to successfully mounted /proc and /sys without explicit problems; access to /proc/* and /sys/* worked fine as well. Then what are the purposes of the sourceDevice field for 'virtual' file systems? Thanks.
Please help.
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Robinson Tiemuqinke wrote:
Please help.
Looking at my BIND init scripts it calls this: mount --bind /proc ${ROOTDIR}/proc >/dev/null
[root@prod-utility-1 init.d]# mount | grep proc /dev/proc on /proc type proc (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) /proc on /var/named/proc type none (rw,bind)
Not sure about the sys file system, maybe it's the same, maybe it's not.
nate
On Thu, 2008-02-21 at 11:45 -0800, nate wrote:
Robinson Tiemuqinke wrote:
Please help.
Looking at my BIND init scripts it calls this: mount --bind /proc ${ROOTDIR}/proc >/dev/null
[root@prod-utility-1 init.d]# mount | grep proc /dev/proc on /proc type proc (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) /proc on /var/named/proc type none (rw,bind)
Not sure about the sys file system, maybe it's the same, maybe it's not.
For the Q posed by the OP, "man mount" gives this hint.
======================================= The proc file system is not associated with a special device, and when mounting it, an arbitrary keyword, such as proc can be used instead of a device specification. (The customary choice none is less fortunate: the error message 'none busy' from umount can be confusing.) =======================================
Note also the default mounts my CentOS 4.x shows
$ mount none on /proc type proc (rw) none on /sys type sysfs (rw) none on /dev/pts type devpts (rw,gid=5,mode=620) usbfs on /proc/bus/usb type usbfs (rw) none on /dev/shm type tmpfs (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
On proc, sys, pts and shm, the "none" comes from /etc/fstab, modified by fstab-sync (see the man page for it). But IIRC from long ago, anything that doesn't have a real device associated with it, like these, can take any value for the fs type. Back then, sentiment was sidling towards avoiding "none" due to the potential confusion it could cause in casual users and the fact that hum0n eyes could more quickly scan and identify desired items when a "rational" value appeared in place of "none".
Note that the sunrpc is different - it seems to be a result of the loaded module sunrpc.
$ /sbin/modinfo sunrpc filename: /lib/modules/2.6.9-67.0.4.EL/kernel/net/sunrpc/sunrpc.ko license: GPL vermagic: 2.6.9-67.0.4.EL 686 REGPARM 4KSTACKS gcc-3.4 depends:
Lsmod shows a use count of one, but I don't see any module using it.
However, the modinfo output in conjunction with output of this command (I won't include the output, there's more than a line or two) makes me think that's it's a foundation piece for RPC stuff.
$ gunzip </boot/symvers-2.6.9-67.0.4.EL.gz |grep sun
The sunrpc mount is mounted by an action not related to a normal mount call, apparently the actions related to starting up RPC, for NFS in my case.
Summary: I *think* it matters not what is in the entries for items that are not associated with real devices.
MHO: it was inane for the RH folks, and others in the world, to continue to use "none" for *decades* after it has been deprecated.
nate
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nate -
Robinson Tiemuqinke -
William L. Maltby