On 04/13/2018 12:08 PM, Max Reitz wrote: >>>> With 512 byte clusters and 64 bit refcount entries I still get 8 PB, >>>> way over what's limited by the L1/L2 tables (128 GB). >>> >>> Do I need to make any modifications to the sentence, then? >> >> I guess what surprised me the first time that I read it was that it >> suggests that this has to be taken into account when calculating the >> physical limits of an image, while in practice it can be ignored. >> >> You could say something like >> >> Although the larger the cluster size, the larger the offsets that can >> be covered by the refcount table, in practice these limits cannot be >> reached because they are larger than the ones imposed by other data >> structures. > > Are there any updates here? I guess I personally would just drop the > whole paragraph, because I think it really doesn't matter...
Yeah, I need to post a v5 of this series now that 2.13 is nearly open. > > Also note that the maximum file size of ext4 is 16 PB (for 4 kB blocks). > OK, it's bigger for XFS, but that still gives some perspective. > > Also, long before anyone is going to complain about the specification > failing to mention that limit, they are going to complain that qemu > refuses to open their image (because of its limit on the reftable size). > > Max > >> although I'm sure that you can come up with a better wording than mine :) >> >> Berto >> > > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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