[DRBD-user] size of DRBD writes

Tim Wood twwood at gmail.com
Mon Mar 1 23:10:59 CET 2010

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

If I make a small update to a file, for example overwriting just the first
byte, will DRBD send the full disk block that was modified, or does it just
send the data for the actual write (1 byte)?  Clearly the latter would be
more efficient, but I'm not certain it is possible.

If it is the first option, is it sending a 1KB disk block, or is the block
size determined by the file system-- 4KB in my case?

I ask because I'm trying to estimate the bandwidth that will be required by
an app when using drbd, and my plan had been simply use iostat to measure
the average block writes/second and then multiply by the size of a block.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20100301/542e31d5/attachment.htm>

More information about the drbd-user mailing list