David Robinson wrote:
Jordi Prats wrote:Hi, I'm the system administrator of PADICAT (http://www.padi.cat). It collects Catalan (http://en.wikipedia.org/wiki/Catalonia) web sites to provide permanent access to them (http://www.padi.cat/en/quees.php). It's equivalent to Internet Archive (http://www.archive.org) but for a particular culture. Our software developers require us to have one large file system, actually a single directory, with all this historically-classified web sites on a gziped file. I'm currently studying lustre and other HPC-related file systems to get this large file system, but by now I have ext3 as our file system. Next Monday I'm planning to extend it to 3TB o 4TB, so I'm currently researching for restrictions because during next month I'll have between 3TB to 4TB more to add: so, it will become a 8TB file system. Last time I fsck my 2'1TB file system I spend about 2 hours. Anyway, I'm also curious about the maximums :PThe man page for vgcreate talks a little bit about limits:"If the volume group metadata uses lvm1 format, extents can vary in size from 8KB to 16GB and there is a limit of 65534 extents in each logical volume. The default of 4 MB leads to a maximum logical volume size of around 256GB. If the volume group metadata uses lvm2 format those restrictions do not apply, but having a large number of extents will slow down the tools but have no impact on I/O performance to the logical volume."In short, you're more likely to reach filesystem limits before LVM's. EXT3 has a theoretical limit of 32 TB, but 32 GB its not practical. Creating an EXT3 filesystem larger than 8 TB is umm, brave - as you have noticed the tools (eg. fsck) do not scale well w/ EXT3.
With a 4K block size the theoretical limit is 16TB. The ext2/3 tools do not work beyond 4TB, or at least they didn't as of a year or two ago. I did report the problem to Theodore, not sure if the fix was ever adopted, but you're absolutely right about the scalability problems of ext3. An fsck of a 16TB filesystem was something that definitely required tea.
GFS or XFS (or others) may be more suitable, but it depends on your requirements.
Any of the extent based filesystems. A fixed format filesystem like ext3 does not scale.