Simple question: does anyone have  a CRC32 executable that will run under unRaid? I know MD5 is available but I'd prefer CRC32 for a couple of reasons:

(1) having 25 TBytes of data to periodically check,  I'd like a faster hash (I can live with a 32-bit hash).

(2) I currently check my unRaid files using the Window's software Exactfile that can calculate CRC32. But this is calculated across the LAN (slower, and reduces LAN bandwidth available for other needs) so an executable that runs under unRaid would be ideal.

 

Does anyone have such a executable that I can beg, borrow, or steal? 

It would need to be able to gracefully handle large files (e.g. 50 GByte ISOs). Most of the C implementations on the net I've found require the entire file data placed in a memory buffer, so only practical for smallish files. 

 

Thanks in advance.

 

 

http://zakalwe.fi/~shd/foss/cksfv/

Did you tried this one? Quick look at code seems it uses just a 16k buffer, not entire file placed on memory buffer.

 

Anyway, would be a lot better you hash files with md5... performance is not a valid reason, unless you have a really old server... else md5 calculation should be actually fast, comparing with the speed your hdd's can read data, then no disadvantage at all in using it. Try to md5sum a big file on your server and at same time check your cpu usage with top and see if really worth using crc32...

On my server I've observed that md5sum does the job about 50% faster than cksfv.  So I keep cksfv only for stuff that comes accompanied by .sfv files from the original publishers, so I can verify that the stuff got to me without any corruption in transit.  But for checksums that I create I naturally use md5sum.