This really cleared things up, thanx! Just one more question: Do you know of a reliable method of comparing sizes in this scenario?
Sturla On Fri, October 20, 2006 11:33, Daniele P. wrote: > On Thursday 19 October 2006 23:19, Sturla Holm Hansen wrote: >> Hmm, just wondering, would hardlinks report different sizes too? > > Remember a file stored as an hard link. > Definitely yes. du, by default, reports the size of the file on disk. > The size of the file on disk is file dependent on your file system and > on the block-size you choose when you use mkfs. > To get the apparent size (which is for me the real file size, it's > called apparent because of sparse file, I guess) you have to use the -b > option. > But remember that the apparent size of directories is still file system > dependent. > > To complicate things the du man page also refers that the apparent size > could be increased by fragmentation and indirect blocks. > I don't think this is true. > It sound strange to me since du uses st_size from stat and st_size > in the SUS is defined: "For regular files, the file size in bytes". > So st_size should be independent from the file system. > The du info manual (for --apparent) also explain: > Print apparent sizes, rather than disk usage. The apparent size > of a file is the number of bytes reported by `wc -c' on regular > files, or more generally, `ls -l --block-size=1' or `stat --format=%s'. > >> Since this is a sync of /var/lib/backuppc which contains a LOT of >> hardlinks this could explain the size-difference.... > > You really want to say that /var/lib/backuppc contains a lot of files > with hard link count grater than 1. > And you hit another strange behaviour! > The size reported by du isn't absolute! It depends on "how you ask"! > > $ ls > $ du -b > 6 . > $ mkdir a > $ du -b ./a > 6 ./a > $ du -b > 6 ./a > 20 . > $ mkdir b > $ du -b ./b > 6 ./b > $ du -b > 6 ./a > 6 ./b > 34 . > $ echo 'test' > a/test > $ du -b ./a/test > 5 ./a/test > $ du -b ./a > 22 ./a > $ du -b > 22 ./a > 6 ./b > 50 . > $ ln a/test b/link > $ du -b ./b/link > 5 ./b/link > $ du -b ./b > 11 ./b > $ du -b > 22 ./a > 6 ./b > 50 . > > See that ./b one time is 11 and one time is 6 and realise the real > meaning of the brief description of du: *estimate* file space usage. > > Regards, > Daniele > > > -- > To UNSUBSCRIBE, email to [EMAIL PROTECTED] > with a subject of "unsubscribe". Trouble? Contact > [EMAIL PROTECTED] > > -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
