From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul B. Henson Date: Mon, 17 Mar 2014 18:07:50 -0700 Subject: cache support In-Reply-To: <7A62EBEE-E031-469E-902B-FA507CADD9DA@redhat.com> References: <096101cf2214$d241ed60$76c5c820$@acm.org> <52F205CA.1090807@redhat.com> <0a3901cf22af$ae01d2d0$0a057870$@acm.org> <52F2AD44.8030006@redhat.com> <0a7b01cf22db$da3f56c0$8ebe0440$@acm.org> <0fff01cf276c$d059c8d0$710d5a70$@acm.org> <0C83CD55-18B6-4407-9A42-72F9D6C5683D@redhat.com> <0b4501cf3d85$44b76c90$ce2645b0$@acm.org> <7A62EBEE-E031-469E-902B-FA507CADD9DA@redhat.com> Message-ID: <0f9a01cf4246$7db93f30$792bbd90$@acm.org> List-Id: To: lvm-devel@redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit > From: Brassow Jonathan > Sent: Monday, March 17, 2014 8:56 AM > > Yes, that is basically the idea. However, converting the thinpool is a little > more tricky. You already are using the fast device for the thinpool metadata > device (which seems awfully large from your example). When you cache the > thinpool, I think you just want to cache the data section. > # lvconvert --type cache --cachepool vg/cachepool vg/thinpool_tdata Ah right; in your original example you had connected the cache to the thinpool data lv before creating the actual thinpool, when I tried to convert that to adding the cache after the fact I didn't take that into consideration. In your original example, it said to size the metadata device to approximately 1/1000 of the data lv size, so for a 4 TB data lv that would actually be almost 4 GB? The estimation utility says about 2.4 GB: # thin_metadata_size -b 64k -s 4t -m 100000 -u g thin_metadata_size - 2.41 gigabytes estimated metadata area size Evidently online metadata pool resize is supported now, so I guess I don't have to extremely overestimate from the start, as long as I keep an eye on it I can always top it off before it runs out. Thanks.