Changwei Ge
2017-Sep-20 05:19 UTC
[Ocfs2-devel] Mixed mounts w/ different physical block sizes (long post)
On 2017/9/19 14:47, Michael Ulbrich wrote:> Hi Changwei, > > thanks for looking into this! > > On 19/09/17 05:32, Changwei Ge wrote: > >> Could you please also provide information about *slot_map*, just type >> "slotmap" in debugfs.ocfs2 tool. This will be helpful to analysis your case. >> >> Please also paste output generated by : >> cat /sys/kernel/config/cluster/<you cluster name>/heartbeat/<file system >> UUID> >> So we see how your cluster is configured. >> Files like block_bytes, blocks and start_block are preferred. > > Ok, here we go. The 4k fs is currently mounted on 6 nodes: > > hb > node: node seq generation checksum > 8: 1 0000000059c0b87d 4b54662f8a10a4c6 ce05089c > 16: 2 0000000059c0b87d 2e78b067074950f9 057c9608 > 24: 3 0000000059c0b87c 46f4e173012a4b7b a2073bec > 40: 5 0000000059c0b87b c0a8e3023e9edaa6 bbca2048 > 48: 6 0000000059c0b87c 304d8bc8e22383a2 2f6002e6 > 64: 8 0000000059c0b87c 8d9c95c4b0296c70 f5e8d50a > > And the associated slot map: > > slotmap > Slot# Node# > 0 1 > 1 2 > 2 3 > 3 6 > 4 5 > 5 8 > > Info from /sys/kernel/config/cluster/ocfs1_cluster/heartbeat/<UUID>Um. You mentioned that when the 8th node mounted the file system heartbeat sequence mismatching showed up. But I can only see 6 nodes here. Is this the scenario where your case happened?> > block_bytes: 4096 > blocks: 255 > start_block: 273> >>> Operation is stable so far. No 'Heartbeat sequence mismatch' errors. >>> Still strange the "times 8" values in column "node:" but this may be a >>> purely aesthetical issue. >> I suppose this is because debugfs.ocfs2 *assumes* that block devices are >> all 512 bytes formatted. >> Perhaps we can improve this. > > Yep, that would be great! > > And what about this scenario of mixed mounts partly from nodes accessing > the device based on 512 byte sectors and partly from nodes seeing it as > a 4k device: should this be avoided or is it supposed to work because > ocfs2 internally maps the different sized sectors to a common structure > in the heartbeat region? >How can this happen? Do you mean that a unique physical disk device which is accessed by different nodes shows different block sizes (512 bytes and 4k)? For example, node A accesses disk by block size - 512 bytes, however, node B accesses the *same* disk by block size - 4k. Thanks, Changwei.> Thanks again ... Michael >