Pre-allocate files

Make sure the target filesystem has enough free space. The space may not be "exclusive" per-say but you can always use File Locks to do that. S: If you end up realizing hard drives are slow and useless or meant to use RAM from the start you can use the ByteBuffer object from java. The allocate and allocateDirect methods should be more than enough.

The byte buffer will be allocated into RAM and possible SwapFile and will be exclusive to this java program. Random access can be done by changing the position of the buffer.

Read more on RandomAccessFile here. Read more on FileLock the java object here. Read more on ByteBuffer here. On Linux systems you can use fallocate system call. It's extremely fast. Just run Bash command. You can pre-allocate space by writing a large file, but to be honest I wouldn't bother. How are we doing? Please help us improve Stack Overflow. Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more. Pre-allocating drive space for file storage Ask Question. AFAIK libtorrent allocates the file upon start writing zeros that's why it takes a long time for big files. There isn't much I can do about that. Sorry, something went wrong. Very strange, as I have zero-filled files before and generally they seem to have written quite quickly. It does it differently on different platforms.

Which platform are you on? Files on windows are by default not sparse, so this will allocate storage on disk. If a file is opened in sparse mode and for writing the sparse flag will be set first:. Skip to content. Star New issue. Jump to bottom. Copy link. I am unsure how this works in qBitTorrent. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Preallocating file space in C?

Ask Question. Asked 13 years, 3 months ago. Active 3 years, 10 months ago. Viewed 6k times. WriteAllBytes filename, new byte[f. Length] ; It works, atleast until you download a file that is several hundred MB's, or potentially even GB's and you throw Windows into a thrashing frenzy if not totally wipe out the pagefile and kill your systems memory altogether.

So, with a little more enlightenment, I set out with the following algorithm. Write buff, 0, buff. Write buff, 0, f. Matthew Scharley Matthew Scharley k 51 51 gold badges silver badges bronze badges. Add a comment. Active Oldest Votes. The syntax: public override void SetLength long value. TylerH Is there a way to make this perform instant file initialization, if volume maintenance privilege is held?