Preallocate space and avoid fragmentation of files — at Version 25
|Reported by:||wOxxOm||Owned by:||Underground78|
|Component version:||Operating system type:|
|Operating system version:|
Description (last modified by )
On Windows platforms newer than WinXP besides SetFilePointer+SetEndOfFile preallocation method which fills required disk space with zeros which might take a lot of time in case of a very large file, there is another literally instant function: SetFileValidData (see MSDN), it just claims disk space leaving intact whatever data there was.
Despite common belief that fragmentation isn't an issue, it's quite the opposite - 1+GB files downloaded in such applications as FileZilla Client which doesn't preallocate disk space, are extremely slow to copy and work with when mounted and impose absolutely unnecessary huge load on HDD due to a lot of disk seeks.
Apparently only a few win32 ftp clients can preallocate space and none of them uses SetFileValidData. Out of about 20 most popular ftp clients I've tested, only Flashget and NetTransport had the feature. Actually I've searched all files on my PC and out of hundreds of small and large win32 apps that constantly deal with creation of files, large and small, only VirtualDub and uTorrent use SetFileValidData, also the latter allows user to select whether he prefers instant preallocation, complete with zeroing or none of the two.
There was a similar ticket (#1486) 7 years ago and now it's already 2012 but FileZilla Client still doesn't preallocate space.
Change History (29)
comment:4 by , 7 years ago
|Summary:||Preallocate space and avoid fragmentation of files with SetFileValidData → Preallocate space and avoid fragmentation of files|