On Sep 14, 2009 22:08 +0100, Peter Grandi wrote: > > When you deal with systems that store millions of files, > > Millions of files may work; but 1 billion is an utter absurdity. > A filesystem that can store reasonably 1 billion small files in > 7TB is an unsolved research issue... I'd disagree. We have Lustre filesystems with 500M files on the ext4(ish) metadata server, and these are only 4TB. Note there is NO DATA in the metadata files, so it isn't quite like a normal filesystem. It also depends on what you mean by "small files". We've previously discussed storing small file data in an extended attribute, and if you are tuning for this and the file size is small enough (3kB or less) the file data could be stored inside the inode (i.e. zero seek data IO). > > fsck time has improved quite a lot recently with ext4 (and > > with xfs). > > How many months do you think a 7TB filesystem with 1 billion > files would take to 'fsck' even with those improvements? Even > with the nice improvements? I think you aren't backing your comments with any facts. The e2fsck time on our MDS filesystems with 500M IN USE inodes is on the order of 4 hours (disk-based RAID-1+0 array). If this was on a RAID-1+0 SSD it could be noticably faster. Ric also commented previously about single-digit hours for e2fsck on a test 1B file ext4 filesystem. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. _______________________________________________ Ext3-users mailing list Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
