Messages in this thread | | | Date | Fri, 05 Jul 2002 19:29:24 +0400 | From | Hans Reiser <> | Subject | Re: [reiserfs-dev] Results of testing Reiserfs on large block devices. |
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Peter Chubb wrote:
>Hi folks, > I couldn't get Reiserfs to work on large devices. I've tracked the >problem down. > > When Reiserfs is mounted, it tries to allocate a chunk of memory for >bitmaps using kmalloc. The largest chunk allocatable by kmalloc is >128k. This limits the size of a reiserfs to just under 2TB on a >64-bit platform (16384 bitmaps times 8bytes per pointer) or just under >4TB on a 32 bit platform (32768 bitmaps times 4bytes per pointer). > >This reasoning assumes that the number of bitmaps is given by the >formula (number_of_blocks + (8 * blocksize - 1))/(8 * blocksize) where >blocksize is 4096 bytes. Thus > number_of_blocks = 8 * 4096 * (16384 - 1) - 1 [64 bit] > > number_of_blocks = 8 * 4096 * (32768 - 1) - 1 [32 bit] > >Hacking mm/slab.c to increase the memory limit allowed larger >filesystems to be mounted, but I haven't tested these thoroughly yet. >-- >Dr Peter Chubb peterc@gelato.unsw.edu.au >You are lost in a maze of BitKeeper repositories, all almost the same. > > > > > Thanks for figuring this out. Oleg will fix it.
-- Hans
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