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SubjectRe: VFAT truncate performance
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Mattias Rönnblom <hofors@lysator.liu.se> writes:

> extending files by ftruncate(2) runs very slow on VFAT file
> systems. On my USB harddisk w/ VFAT, it takes 14 seconds to extend an
> empty file to 1 GB. On a memory stick, it takes well over 4 minutes.
>
> My question is: is this problem on the conceptual level (ie there is
> no way of extending files on FAT that doesn't involve many disk
> operations) or is the current Linux fs driver suboptimal in this
> respect?

Unfortunately FAT doesn't support sparse file, so ftruncate(2) which
extend size needs to fill all clusters with zero, and write data.

This is limitation of FAT filesystem.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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