[DRBD-user] using drbd on software raid

Lars Ellenberg Lars.Ellenberg at linbit.com
Mon May 31 20:24:17 CEST 2004

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


/ 2004-05-31 12:03:55 -0600
\ Lucas Albers:
> 
> Lars Ellenberg said:
> > +   #  and I see "access beyond end of device" in some rare cases, when
> > +   #  someone tries to access the last logical block with full block
> > +   #  size, but it is some sectors shorter -- not drbd's fault, anyways)
> > +   # it is probably best rounded _down_ to the next multiple of 4
> > +   disk-size = 12345678k
> >     ^^^^^^^^^
> 
> So assuming my size for my software raid is thus:
> md4 : active raid5 hdh4[3] hdg4[2] hdf4[1] hde4[0]
>       356958720 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
> 
> I should set my size in drbd to: 356958720 - 4

since 356958720 *is* already modulo 4,
you don't need to subtract anything.
fdisk -s /dev/md4 # should report the same number, btw.

> Can we make a wiki for drbd?
> Similar to this wiki, to keep you from the pain of answering the same
> questions over and over?

well, we have a faq. but yes, it is outdated.
and yes, we plan to have a wiki. soonish...

	Lars Ellenberg



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