[DRBD-user] Question about no-disk-flushes, no-md-flushes

Lars Ellenberg lars.ellenberg at linbit.com
Thu Aug 14 15:08:03 CEST 2008

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

On Thu, Aug 14, 2008 at 11:23:39AM +0200, Matthias Weigel wrote:
> Hello,
> where exactly do disk flushes happen without this option?
> - per IO?

"disk-flushes" per drbd-barrier, which in turn are inserted between
reorder-domains to keep write ordering on the nodes in proper order.

"md-flushes" for every meta data access, i.e. al update or bm update.

> With no-disk-flushes and no-md-flushes active, does a flush happen,
> when  i say "sync"?

different concept.
different levels of "flush".
so, the answer is "no", but probably the
answer to what you mean would actually be yes.

sorry, this is not easily put into two sentences.

: Lars Ellenberg                
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting    http://www.linbit.com

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