On Mon, Jan 10, 2011 at 12:51 PM, J. Ryan Earl <span dir="ltr"><<a href="mailto:oss@jryanearl.us">oss@jryanearl.us</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">On Thu, Jan 6, 2011 at 1:23 PM, J <span dir="ltr"><<a href="mailto:j@koarcg.com" target="_blank">j@koarcg.com</a>></span> wrote:</div><div class="gmail_quote"><div class="im"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
In a related question. Is it possible to take a snapshot of the secondary volume while the drbd is active? I can't find the exact link, but the user's guide mentioned not accessing the secondary AT ALL while the primary was active. I assumed that would include taking snapshots of the secondary?</blockquote>
<div><br></div></div><div>A DRBD device in secondary mode will not be accessible in anyway. IIRC, the /dev/drbdX device won't even exist at this point. If you're using protocol C and have the DRBD resource on top of LV, you can still snapshot it and the snapshot should be consistent for a point-in-time.</div>
<div><br></div><font color="#888888"><div>-JR</div></font></div>
</blockquote></div><br><div>I should say, you can still snapshot it on [the secondary node at the time]...</div><div><br></div><div>Otherwise, if you're running active-passive with LVM on-top of DRBD, then the snapshot can only be instigated by the primary and the snapshot CoW volume will be replicated to the secondary. Keep in mind, DRBD + Snapshotting will impose triple overhead on writes.</div>
<div><br></div><div>-JR</div>