progress block size and file system block size-relation

[richieasir]

hi to all,
while am going through the document,i read that The possible blocksizes Progress can use are 1k, 2k, 4k and 8k.
Most commonly you choose a blocksize which is equal to or a multiple of your file system blocksize.

what is this file system block size and how to find it(am using linux)?

regards
Richards

 

[TomBascom]

Filesystem block sizes aren't really relevant anymore. Most modern filesystems aren't organized so simply as that. OTOH Linux (and Windows and a lot of other UNIXes) use 4k blocks in the kernel and that is the "natural" unit for a lot of things. So either a 4k or an 8k db block will work best for most modern operating systems. You generally want to use a block that is a multiple of the natural size -- it's ok to be bigger but not ok to be smaller.

I usually find that 8k is only slightly better than 4k on Linux.

Another thing to consider is that there is a slight chance of a "torn page" if you choose 8k blocks -- this is a situation where a HW crash might result in one half of an 8k block being updated and the other half not. Current release of OpenEdge are not vulnerable to this because they have a checksum which will detect it. But older releases could, in theory, get corrupted that way. (If it actually happens in the real world it is very rare.)