diff options
Diffstat (limited to 'Documentation/device-mapper/thin-provisioning.txt')
| -rw-r--r-- | Documentation/device-mapper/thin-provisioning.txt | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt index 1699a55b7b70..4bcd4b7f79f9 100644 --- a/Documentation/device-mapper/thin-provisioning.txt +++ b/Documentation/device-mapper/thin-provisioning.txt @@ -112,9 +112,11 @@ $low_water_mark is expressed in blocks of size $data_block_size. If free space on the data device drops below this level then a dm event will be triggered which a userspace daemon should catch allowing it to extend the pool device. Only one such event will be sent. -Resuming a device with a new table itself triggers an event so the -userspace daemon can use this to detect a situation where a new table -already exceeds the threshold. + +No special event is triggered if a just resumed device's free space is below +the low water mark. However, resuming a device always triggers an +event; a userspace daemon should verify that free space exceeds the low +water mark when handling this event. A low water mark for the metadata device is maintained in the kernel and will trigger a dm event if free space on the metadata device drops below @@ -274,7 +276,8 @@ ii) Status <transaction id> <used metadata blocks>/<total metadata blocks> <used data blocks>/<total data blocks> <held metadata root> - [no_]discard_passdown ro|rw + ro|rw|out_of_data_space [no_]discard_passdown [error|queue]_if_no_space + needs_check|- transaction id: A 64-bit number used by userspace to help synchronise with metadata @@ -394,3 +397,6 @@ ii) Status If the pool has encountered device errors and failed, the status will just contain the string 'Fail'. The userspace recovery tools should then be used. + + In the case where <nr mapped sectors> is 0, there is no highest + mapped sector and the value of <highest mapped sector> is unspecified. |