On Thu, Jul 9, 2020 at 10:33 AM Marc Roos <M.Roos@xxxxxxxxxxxxxxxxx> wrote: > > What about ntfs? You have there a not quick option. Maybe it writes to > the whole disk some random pattern. Why do you ask? > I am writing an API layer to plug into our platform, so I want to know if the format times can be deterministic or unbounded. From what I saw with ext3, ext4 and xfs volumes, the format time is actually not dependent on the size of the volume, so I just wanted to confirm if we can assume that, or if I am missing something. Thanks, Shridhar > > > -----Original Message----- > Cc: ceph-users > Subject: Re: RBD thin provisioning and time to format a > volume > > Thanks Jason. > > Do you mean to say some filesystems will initialize the entire disk > during format? Does that mean we will see the entire size of the volume > getting allocated during formatting? > Or do you mean to say, some filesystem formatting just takes longer than > others, as it does more initialization? > > I am just trying to understand if there are cases where Ceph will > allocate all the blocks for a filesystem during formation operations, OR > if they continue to be thin provisioned (allocate as you go based on > real data). So far I have tried with ext3, ext4 and xfs and none of them > dont allocate all the blocks during format. > > -Shridhar > > > On Thu, 9 Jul 2020 at 06:58, Jason Dillaman <jdillama@xxxxxxxxxx> wrote: > > > On Thu, Jul 9, 2020 at 12:02 AM Void Star Nill > > <void.star.nill@xxxxxxxxx> > > wrote: > > > > > > > > > > > > On Wed, Jul 8, 2020 at 4:56 PM Jason Dillaman <jdillama@xxxxxxxxxx> > > wrote: > > >> > > >> On Wed, Jul 8, 2020 at 3:28 PM Void Star Nill > > >> <void.star.nill@xxxxxxxxx> > > wrote: > > >> > > > >> > Hello, > > >> > > > >> > My understanding is that the time to format an RBD volume is not > > dependent > > >> > on its size as the RBD volumes are thin provisioned. Is this > correct? > > >> > > > >> > For example, formatting a 1G volume should take almost the same > > >> > time > > as > > >> > formatting a 1TB volume - although accounting for differences in > > latencies > > >> > due to load on the Ceph cluster. Is that a fair assumption? > > >> > > >> Yes, that is a fair comparison when creating the RBD image. > > >> However, a format operation might initialize and discard extents on > > > >> the disk, so a larger disk will take longer to format. > > > > > > > > > Thanks for the response Jason. Could you please explain a bit more > > > on > > the the format operation? > > > > I'm not sure what else there is to explain. When you create a file > > system on top of any block device, it needs to initialize the block > > device. Depending on the file system, it might take more time for > > larger block devices because it's doing more work. > > > > > Is there a relative time that we can determine based on the volume > size? > > > > > > Thanks > > > Shridhar > > > > > > > > >> > > >> > > >> > Thanks, > > >> > Shridhar > > >> > _______________________________________________ > > >> > ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send > > > >> > an email to ceph-users-leave@xxxxxxx > > >> > > > >> > > >> > > >> -- > > >> Jason > > >> > > > > > > -- > > Jason > > > > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an > email to ceph-users-leave@xxxxxxx > > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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