High queue depth, sequential, direct IO. With appropriate striping settings, instead of all the sequential IO being processed by the same PG sequentially, the IO will be processed by multiple PGs in parallel. -- Jason Dillaman ----- Original Message ----- > From: "Василий Ангапов" <angapov@xxxxxxxxx> > To: "Jason Dillaman" <dillaman@xxxxxxxxxx> > Cc: "Bill WONG" <wongahshuen@xxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx> > Sent: Friday, January 29, 2016 11:04:52 AM > Subject: Re: Striping feature gone after flatten with cloned images > > Btw, in terms of fio for example - how can I practically see the > benefit of striping? > > 2016-01-29 22:45 GMT+08:00 Jason Dillaman <dillaman@xxxxxxxxxx>: > > That was intended as an example of how to use fancy striping with RBD > > images. The stripe unit and count are knobs to tweak depending on your IO > > situation. > > > > Taking a step back, what are you actually trying to accomplish? The > > flatten operation doesn't necessarily fit the use case for this feature. > > Instead, it is useful for applications that issue many small, sequential > > IO operations. If you set your stripe unit to be the IO size (and > > properly align it), the IO load will be able to be distributed to more > > OSDs in parallel. > > > > -- > > > > Jason Dillaman > > > > > > ----- Original Message ----- > > > >> From: "Bill WONG" <wongahshuen@xxxxxxxxx> > >> To: "Jason Dillaman" <dillaman@xxxxxxxxxx> > >> Cc: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> > >> Sent: Friday, January 29, 2016 12:30:24 AM > >> Subject: Re: Striping feature gone after flatten with cloned > >> images > > > >> Hi Jason, > > > >> it works fine.... but flatten take how longer than than before.. > >> i would like to know how to decide the --stripe-unit & --stripe-count to > >> gain > >> the best performance? > >> i see you put unit of 4K and count with 16.. why? > >> -- > >> --stripe-unit 4K --stripe-count 16 > >> -- > > > >> thank you! > > > >> On Fri, Jan 29, 2016 at 11:15 AM, Jason Dillaman < dillaman@xxxxxxxxxx > > >> wrote: > > > >> > When you set "--stripe-count" to 1 and set the "--stripe-unit" to the > >> > object > >> > size, you have actually explicitly told the rbd CLI to not use "fancy" > >> > striping. A better example would be something like: > >> > > > >> > rbd clone --stripe-unit 4K --stripe-count 16 storage1/cloudlet-1@snap1 > >> > storage1/cloudlet-1-clone > >> > > > >> > -- > >> > > > >> > Jason Dillaman > >> > > > >> > ----- Original Message ----- > >> > > > >> > > From: "Bill WONG" < wongahshuen@xxxxxxxxx > > >> > >> > > To: "Jason Dillaman" < dillaman@xxxxxxxxxx > > >> > >> > > Cc: "ceph-users" < ceph-users@xxxxxxxxxxxxxx > > >> > >> > > Sent: Thursday, January 28, 2016 10:08:38 PM > >> > >> > > Subject: Re: Striping feature gone after flatten with > >> > > cloned > >> > >> > > images > >> > > > >> > > hi jason, > >> > > > >> > > how i can make the stripping parameters st the time of clone creation? > >> > > as > >> > > i > >> > >> > > have tested, which looks doesn't work properly.. > >> > >> > > the clone image still without stripping.. any idea? > >> > >> > > -- > >> > >> > > rbd clone --stripe-unit 4096K --stripe-count 1 > >> > > storage1/cloudlet-1@snap1 > >> > >> > > storage1/cloudlet-1-clone > >> > >> > > rbd flatten storage1/cloudlet-1-clone > >> > >> > > rbd info storage1/cloudlet-1-clone > >> > >> > > rbd image 'cloudlet-1-clone': > >> > >> > > size 1000 GB in 256000 objects > >> > >> > > order 22 (4096 kB objects) > >> > >> > > block_name_prefix: rbd_data.5ecd364dfe1f8 > >> > >> > > format: 2 > >> > >> > > features: layering > >> > >> > > flags: > >> > >> > > --- > >> > > > >> > > On Fri, Jan 29, 2016 at 3:54 AM, Jason Dillaman < dillaman@xxxxxxxxxx > >> > > > > >> > >> > > wrote: > >> > > > >> > > > You must specify the clone's striping parameters at the time of its > >> > >> > > > creation > >> > >> > > > -- it is not inherited from the parent image. > >> > >> > > > >> > > > >> > > > -- > >> > >> > > > >> > > > >> > > > Jason Dillaman > >> > >> > > > >> > > > >> > > > ----- Original Message ----- > >> > >> > > > >> > > > >> > > > > From: "Bill WONG" < wongahshuen@xxxxxxxxx > > >> > >> > > > >> > >> > > > > To: "ceph-users" < ceph-users@xxxxxxxxxxxxxx > > >> > >> > > > >> > >> > > > > Sent: Thursday, January 28, 2016 1:25:12 PM > >> > >> > > > >> > >> > > > > Subject: Striping feature gone after flatten with > >> > > > > cloned > >> > >> > > > > images > >> > >> > > > >> > > > >> > > > > Hi, > >> > >> > > > >> > > > >> > > > > i have tested with the flatten: > >> > >> > > > >> > >> > > > > 1) make a snapshot of image > >> > >> > > > >> > >> > > > > 2) protect the snapshot > >> > >> > > > >> > >> > > > > 3) clone the snapshot > >> > >> > > > >> > >> > > > > 4) flatten the clone > >> > >> > > > >> > >> > > > > then i found issue: > >> > >> > > > >> > >> > > > > with the original image / snapshot or the clone before flatten, > >> > > > > all > >> > > > > are > >> > >> > > > > with > >> > >> > > > >> > >> > > > > stripping feature, BUT after flattened the clone, then there is no > >> > > > > more > >> > >> > > > >> > >> > > > > Stripping with the clone image...what is the issue? and how can > >> > > > > enable > >> > >> > > > > the > >> > >> > > > >> > >> > > > > striping feature? > >> > >> > > > >> > > > >> > > > > thank you! > >> > >> > > > >> > > > >> > > > > _______________________________________________ > >> > >> > > > >> > >> > > > > ceph-users mailing list > >> > >> > > > >> > >> > > > > ceph-users@xxxxxxxxxxxxxx > >> > >> > > > >> > >> > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >> > >> > > > >> > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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