What writes are done to a volume as a result of mounting and browsing?

davidsanders · 11-12-2009, 05:56 AM

Old mainframe guy trying to learn new tricks. I've found that when a volume has been written to by another host, that after a umount, a mount and looking at the files on the volume, 2 or 3 tracks have had writes to them. I know in MF that there may be change bits or last referenced bits, etc. What would the writes be here?

Agrouf · 11-12-2009, 06:58 AM

Hello,
Your post is not clear to me. What does MF stand for?
Are you asking what the system has written to the disk at mounting and unmounting?
That depends on the filesystem. ext2/3/4 filesystems record the mount time and the number of mounts since last fsck.

jschiwal · 11-12-2009, 07:06 AM

I'm not certain if this will prevent updating volume metadata, but try mounting the partition with the ro option. Also, if you read a file or two, the access times (atime) will have changed unless you use the noatime mount option.

syg00 · 11-12-2009, 07:16 AM

Filesystems in Linux encapsulate the meta-data describing that filesystem. Hence the data you may be used to in a VTOC or VVDS in a different universe is in the meta-data itself. Likewise the journal for a journalling f/s (usually).

davidsanders · 11-13-2009, 07:13 AM

OK, thanks. BTW: MF = mainframe (the big old iron)