I am planning on having a file-system that is over 32TB in the very near future and I heard from someone that JFS can't handle file-systems over 32 TB correctly (can't expand, fsck, or anything). I believe this is indeed true as I just tried formatting a file-system that was 31 TB via a sparse file and it took a bit of time to format and ended up with a file with about 5 GB of usage:
r...@sabayonx86-64: 05:31 PM :/data# mkfs.jfs -s 1024 /data/sparse_jfs mkfs.jfs version 1.1.14, 06-Apr-2009 Warning! All data on device /data/sparse_jfs will be lost! Continue? (Y/N) y - Format completed successfully. 33285996544 kilobytes total disk space. r...@sabayonx86-64: 05:32 PM :~# ls -lsah /data/sparse_jfs 4.9G -rw-r--r-- 1 root root 31T 2010-04-20 17:32 /data/sparse_jfs However, when I made this 2 TB bigger (to 33 TB) the format went much quicker and the end result was a sparse file with only 1.1 GB used: r...@sabayonx86-64: 05:32 PM :/data# mkfs.jfs -s 1024 /data/sparse_jfs mkfs.jfs version 1.1.14, 06-Apr-2009 Warning! All data on device /data/sparse_jfs will be lost! Continue? (Y/N) y - Format completed successfully. 35433480192 kilobytes total disk space. r...@sabayonx86-64: 05:32 PM :/data# ls -lsah /data/sparse_jfs 1.1G -rw-r--r-- 1 root root 33T 2010-04-20 17:33 /data/sparse_jfs So obviously there is some bug here as if anything it should be writing more data. Also the used space amount after mounting it is also about the size I would expect from the sparse file minus the log size: Again used size just about doubles with a 64TB file-system but the sparse file is still much smaller than with a 31 TB file-system: r...@sabayonx86-64: 05:37 PM :/data# dd if=/dev/zero of=sparse_jfs bs=1M count=0 seek=64M 0+0 records in 0+0 records out 0 bytes (0 B) copied, 1.1877e-05 s, 0.0 kB/s r...@sabayonx86-64: 05:37 PM :/data# mkfs.jfs -s 1024 /data/sparse_jfs mkfs.jfs version 1.1.14, 06-Apr-2009 Warning! All data on device /data/sparse_jfs will be lost! Continue? (Y/N) y - Format completed successfully. 68719476736 kilobytes total disk space. r...@sabayonx86-64: 05:38 PM :/data# mount -o loop -t jfs /data/sparse_jfs /mnt/sparse/ r...@sabayonx86-64: 05:38 PM :/data# df -h /mnt/sparse/ Filesystem Size Used Avail Use% Mounted on /data/sparse_jfs 65T 8.1G 64T 1% /mnt/sparse However trying to copy anything to it immediately errors out: r...@sabayonx86-64: 05:39 PM :/mnt/sparse# cp -avf /opt ./ cp: cannot create directory `./opt': Input/output error r...@sabayonx86-64: 05:39 PM :/mnt/sparse# ERROR: (device loop1): dbAllocNext: Corrupt dmap page ERROR: (device loop1): remounting filesystem as read-only ialloc: diAlloc returned -5! With the 32 TB sparse file it works as expected and the cp runs without any problem: r...@sabayonx86-64: 05:40 PM :/data# dd if=/dev/zero of=sparse_jfs bs=1M count=0 seek=31M 0+0 records in 0+0 records out 0 bytes (0 B) copied, 1.2172e-05 s, 0.0 kB/s r...@sabayonx86-64: 05:40 PM :/data# mkfs.jfs -s 1024 /data/sparse_jfs mkfs.jfs version 1.1.14, 06-Apr-2009 Warning! All data on device /data/sparse_jfs will be lost! Continue? (Y/N) y - Format completed successfully. 33285996544 kilobytes total disk space. r...@sabayonx86-64: 05:41 PM :/data# ls -lsah /data/sparse_jfs 4.9G -rw-r--r-- 1 root root 31T 2010-04-20 17:41 /data/sparse_jfs r...@sabayonx86-64: 05:42 PM :/mnt/sparse# df -h /mnt/sparse/ Filesystem Size Used Avail Use% Mounted on /data/sparse_jfs 31T 3.9G 31T 1% /mnt/sparse r...@sabayonx86-64: 05:42 PM :/mnt/sparse# cp -avf /opt/ ./ | wc -l 17426 r...@sabayonx86-64: 05:43 PM :/mnt/sparse# df -h /mnt/sparse/ Filesystem Size Used Avail Use% Mounted on /data/sparse_jfs 31T 5.5G 31T 1% /mnt/sparse r...@sabayonx86-64: 05:43 PM :/mnt/sparse# ls -lsah /data/sparse_jfs 6.0G -rw-r--r-- 1 root root 31T 2010-04-20 17:41 /data/sparse_jfs r...@sabayonx86-64: 05:43 PM :/mnt/sparse# Are there any plans to fix this? Ive got a feeling that its something simple as only the log seems to be written when doing the mkfs. ------------------------------------------------------------------------------ _______________________________________________ Jfs-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jfs-discussion
