Messages in this thread | | | Date | Sun, 21 Mar 1999 12:56:50 -0500 (EST) | From | Alexander Viro <> | Subject | Re: breaking the 2Gigabyte limit on 32 bit arch of inode->i_size (off_t vs loff_t) |
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On Sun, 21 Mar 1999, Andrea Arcangeli wrote:
> On Sat, 20 Mar 1999, Alexander Viro wrote: > > >> so the number of blocks we'll be able to address once we'll broke the > >> i_size limit will be: > >> > >> 12 + 256 + 256^2 + 256^3 -> 16843020 > >> > >> Considering blocksize = 1k we'll be able to address only 16giga according > >> to me. So I'll add a quad level of indirection. This will give as a view > > > > Or we can use 4k blocks and get 256 times more than that. I.e. > >same 4Tb. > > 12 + 1024 + 1024^2 + 1024^3 = 1.074.791.436 -> 4^12 max filesize.
Exactly. 1024^3*4K=4T
> So you think it doesn't worth to have a quad level of indirection to be > allowed to create a filesystem with 1k of blocksize and to be still able > to play with files >16giga, right? Having such level of indirection won't > change the size of the metadata we'll have on disk, but it will allow it > to be more finegrined on the disk side, saving some good bit of space. But > maybe if you have a so big fs you don't care losing a mean of some kbyte > per inode, and probably is better to decrease the complexity of the fs, > right?
To start with, you are *not* going to have a good life with anything along the lines of ext2 on such sizes. Think of the time fsck will take. So I *seriously* doubt that it goes beyond the academical exercise. Moreover, anything beyond 16G is going to have a pretty complex internal structure and most likely will prefer to live on a separate device.
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