No Name Device Size Zone size On
0 nullb0 /dev/nullb0 2048M 128M 1
1 nullb1 /dev/nullb1 1024M 256M 1
The device nullb0 has been created as single/single and a git checkout workload runs there, no problems. After some time, I've tried to add another device, notice different zone size, but a multiple of the first one. The command
does not show it as part of the filesystem, so it failed. There are several messages in the syslog:
[35381.581185] BTRFS info (device nullb0): reclaiming chunk 939524096 with 0% used 0% unusable
[35381.592683] BTRFS info (device nullb0): relocating block group 939524096 flags data
[35382.389707] BTRFS info (device nullb0): found 92 extents, stage: move data extents
[35382.468521] blk_update_request: I/O error, dev nullb1, sector 131072 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[35382.471162] blk_update_request: I/O error, dev nullb1, sector 2093056 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[35382.479590] Buffer I/O error on dev nullb1, logical block 16384, lost async page write
[35382.490645] Buffer I/O error on dev nullb1, logical block 261632, lost async page write
[35382.507123] blk_update_request: I/O error, dev nullb1, sector 2093064 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.507138] Buffer I/O error on dev nullb1, logical block 261633, lost async page write
[35382.507180] Buffer I/O error on dev nullb1, logical block 261634, lost async page write
[35382.507209] Buffer I/O error on dev nullb1, logical block 261635, lost async page write
[35382.507238] Buffer I/O error on dev nullb1, logical block 261636, lost async page write
[35382.507277] Buffer I/O error on dev nullb1, logical block 261637, lost async page write
[35382.507315] Buffer I/O error on dev nullb1, logical block 261638, lost async page write
[35382.507353] Buffer I/O error on dev nullb1, logical block 261639, lost async page write
[35382.507392] Buffer I/O error on dev nullb1, logical block 261640, lost async page write
[35382.585820] blk_update_request: I/O error, dev nullb1, sector 2093312 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.586378] blk_update_request: I/O error, dev nullb1, sector 2093560 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.608819] blk_update_request: I/O error, dev nullb1, sector 2093808 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.620436] blk_update_request: I/O error, dev nullb1, sector 2094056 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.620847] blk_update_request: I/O error, dev nullb1, sector 2094304 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.643332] blk_update_request: I/O error, dev nullb1, sector 2094552 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.643748] blk_update_request: I/O error, dev nullb1, sector 2094800 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[35382.650984] BTRFS info (device nullb0): found 92 extents, stage: update data pointers
Messages with nullb0 are fine and expected, the 'Buffer error' are related to the device addition.
The nullb device setup:
The device nullb0 has been created as single/single and a git checkout workload runs there, no problems. After some time, I've tried to add another device, notice different zone size, but a multiple of the first one. The command
succeeded without warnings on console, but
does not show it as part of the filesystem, so it failed. There are several messages in the syslog:
Messages with nullb0 are fine and expected, the 'Buffer error' are related to the device addition.