]>
Commit | Line | Data |
---|---|---|
9f95a23c | 1 | ===================== |
7c673cae FG |
2 | Experimental Features |
3 | ===================== | |
4 | ||
9f95a23c TL |
5 | CephFS includes a number of experimental features which are not fully |
6 | stabilized or qualified for users to turn on in real deployments. We generally | |
7 | do our best to clearly demarcate these and fence them off so they cannot be | |
8 | used by mistake. | |
7c673cae | 9 | |
9f95a23c TL |
10 | Some of these features are closer to being done than others, though. We |
11 | describe each of them with an approximation of how risky they are and briefly | |
12 | describe what is required to enable them. Note that doing so will | |
13 | *irrevocably* flag maps in the monitor as having once enabled this flag to | |
14 | improve debugging and support processes. | |
7c673cae FG |
15 | |
16 | Inline data | |
17 | ----------- | |
18 | By default, all CephFS file data is stored in RADOS objects. The inline data | |
19 | feature enables small files (generally <2KB) to be stored in the inode | |
20 | and served out of the MDS. This may improve small-file performance but increases | |
21 | load on the MDS. It is not sufficiently tested to support at this time, although | |
22 | failures within it are unlikely to make non-inlined data inaccessible | |
23 | ||
24 | Inline data has always been off by default and requires setting | |
11fdf7f2 | 25 | the ``inline_data`` flag. |
7c673cae | 26 | |
9f95a23c TL |
27 | Inline data has been declared deprecated for the Octopus release, and will |
28 | likely be removed altogether in the Q release. | |
29 | ||
7c673cae | 30 | Mantle: Programmable Metadata Load Balancer |
11fdf7f2 | 31 | ------------------------------------------- |
7c673cae FG |
32 | |
33 | Mantle is a programmable metadata balancer built into the MDS. The idea is to | |
34 | protect the mechanisms for balancing load (migration, replication, | |
35 | fragmentation) but stub out the balancing policies using Lua. For details, see | |
36 | :doc:`/cephfs/mantle`. | |
37 | ||
81eedcae TL |
38 | LazyIO |
39 | ------ | |
40 | LazyIO relaxes POSIX semantics. Buffered reads/writes are allowed even when a | |
41 | file is opened by multiple applications on multiple clients. Applications are | |
42 | responsible for managing cache coherency themselves. |