Ext3 for large filesystems

Ext3 for large filesystems

Posted Mar 12, 2007 15:38 UTC (Mon) by sandeen (guest, #42852)
In reply to: Ext3 for large filesystems by sbergman27
Parent article: Ext3 for large filesystems

> My understanding is that even XFS has a maximum filesystem size of only 16TB on 32 bit, even though it goes to 9 EB on 64 bit systems.

Though xfs is fully 64-bit capable on 32-bit machines, the 16T limit is OS-imposed. There is a 32-bit index into the (4k) page cache on x86, so 2^32 * 4096 is 16T is the maximum offset that can be addressed.

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Ext3 for large filesystems

Posted Mar 20, 2007 16:32 UTC (Tue) by BrucePerens (guest, #2510) [Link]

Not too long ago, Unix systems replaced seek() with the lseek(), and were able to handle longer offsets even though they were 16-bit machines. The word width of your CPU in no way limits the width of words upon which you can perform arithmetic. The new 48-bit field is not using compiler types wider than 32 bits for its implementation. They could use "long long", but I suppose that's less portable.

Bruce