On Wed, Mar 12 2014 at 7:35pm -0400, Mike Snitzer <snitzer@redhat.com> wrote: > On Wed, Mar 12 2014 at 5:21pm -0400, > Paul B. Henson <henson@acm.org> wrote: > > > While researching thinpool provisioning, it seems one of the issues is that > > the size of the metadata is fixed as of creation, and that if the metadata > > allocation fills up, your pool is corrupted? In many of the places that > > concern was mentioned, it was also said that extending the size of the > > metadata lv was a feature coming soon, but I didn't find anything confirming > > whether or not that functionality had been released. Is the size of the > > metadata lv still fixed? > > No, metadata resize is now available. But you definitely want to be > using the latest kernel (there have been various fixes for this > feature). > > Completely exhausting all space in the metadata device will expose you > to a corner case that still needs work... so best to avoid that by > sizing your metadata device conservatively (larger). > > We'll soon be assessing whether a fix is needed for metadata resize once > all metadata space is exhausted (but last I knew we have a bug lurking > in dm-persistent-data for this case). Yes, we're still unable to resize after metadata has been completely exhausted: (NOTE: this is with a hacked 3.14-rc6 kernel that comments out the dm_pool_metadata_set_needs_check() block in drivers/md/dm-thin.c:abort_transaction().. otherwise this test would short-circuit on the 'needs_check' flag being set and would never attempt the resize) # dmtest run --suite thin-provisioning -n /resize_metadata_after_exhaust/ Loaded suite thin-provisioning Started test_resize_metadata_after_exhaust(MetadataResizeTests): metadata_size = 512k Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: reached low water mark for metadata device: sending event. Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: space map metadata: unable to allocate new metadata block Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: metadata operation 'dm_pool_alloc_data_block' failed: error = -28 Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: aborting current metadata transaction Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: switching pool to read-only mode wipe_device failed as expected resizing... Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186096 Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186096 Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: switching pool to write mode Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 128 to 192 blocks Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: space map metadata: unable to allocate new metadata block Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: metadata operation 'dm_pool_commit_metadata' failed: error = -28 Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: aborting current metadata transaction Mar 13 12:57:44 rhel-storage-02 kernel: device-mapper: thin: 251:5: switching pool to read-only mode Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:44 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:45 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:45 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:45 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186111 Mar 13 12:57:45 rhel-storage-02 kernel: Buffer I/O error on device dm-6, logical block 4186104 metadata_size = 768k wipe_device failed as expected resizing... Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: thin: 251:5: switching pool to write mode Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 128 to 256 blocks Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: space map metadata: unable to allocate new metadata block Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: thin: 251:5: metadata operation 'dm_pool_commit_metadata' failed: error = -28 Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: thin: 251:5: aborting current metadata transaction Mar 13 12:57:46 rhel-storage-02 kernel: device-mapper: thin: 251:5: switching pool to read-only mode Good news is online metadata resize works fine as long as metadata space hasn't been exhausted: # dmtest run --suite thin-provisioning -n /resize_metadata_with_io/ Loaded suite thin-provisioning Started test_resize_metadata_with_io(MetadataResizeTests): Mar 13 13:19:10 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 256 to 512 blocks Mar 13 13:19:11 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 512 to 1024 blocks Mar 13 13:19:12 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 1024 to 1536 blocks Mar 13 13:19:14 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 1536 to 2048 blocks Mar 13 13:19:15 rhel-storage-02 kernel: device-mapper: thin: 251:5: growing the metadata device from 2048 to 2560 blocks . Finished in 11.653548028 seconds. _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
