diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-19 12:43:06 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-19 12:43:06 -0400 |
commit | fc7f99cf36ebae853639dabb43bc2f0098c59aef (patch) | |
tree | 3ca7050397f515f91ef98f8b6293f9f7fd84ef02 /Documentation | |
parent | 0a492fdef8aa241f6139e6455e852cc710ae8ed1 (diff) | |
parent | f1a3d57213fe264b4cf584e78bac36aaf9998729 (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (205 commits)
ceph: update for write_inode API change
ceph: reset osd after relevant messages timed out
ceph: fix flush_dirty_caps race with caps migration
ceph: include migrating caps in issued set
ceph: fix osdmap decoding when pools include (removed) snaps
ceph: return EBADF if waiting for caps on closed file
ceph: set osd request message front length correctly
ceph: reset front len on return to msgpool; BUG on mismatched front iov
ceph: fix snaptrace decoding on cap migration between mds
ceph: use single osd op reply msg
ceph: reset bits on connection close
ceph: remove bogus mds forward warning
ceph: remove fragile __map_osds optimization
ceph: fix connection fault STANDBY check
ceph: invalidate_authorizer without con->mutex held
ceph: don't clobber write return value when using O_SYNC
ceph: fix client_request_forward decoding
ceph: drop messages on unregistered mds sessions; cleanup
ceph: fix comments, locking in destroy_inode
ceph: move dereference after NULL test
...
Fix trivial conflicts in Documentation/ioctl/ioctl-number.txt
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/filesystems/ceph.txt | 139 | ||||
-rw-r--r-- | Documentation/ioctl/ioctl-number.txt | 1 |
2 files changed, 140 insertions, 0 deletions
diff --git a/Documentation/filesystems/ceph.txt b/Documentation/filesystems/ceph.txt new file mode 100644 index 000000000000..6e03917316bd --- /dev/null +++ b/Documentation/filesystems/ceph.txt | |||
@@ -0,0 +1,139 @@ | |||
1 | Ceph Distributed File System | ||
2 | ============================ | ||
3 | |||
4 | Ceph is a distributed network file system designed to provide good | ||
5 | performance, reliability, and scalability. | ||
6 | |||
7 | Basic features include: | ||
8 | |||
9 | * POSIX semantics | ||
10 | * Seamless scaling from 1 to many thousands of nodes | ||
11 | * High availability and reliability. No single points of failure. | ||
12 | * N-way replication of data across storage nodes | ||
13 | * Fast recovery from node failures | ||
14 | * Automatic rebalancing of data on node addition/removal | ||
15 | * Easy deployment: most FS components are userspace daemons | ||
16 | |||
17 | Also, | ||
18 | * Flexible snapshots (on any directory) | ||
19 | * Recursive accounting (nested files, directories, bytes) | ||
20 | |||
21 | In contrast to cluster filesystems like GFS, OCFS2, and GPFS that rely | ||
22 | on symmetric access by all clients to shared block devices, Ceph | ||
23 | separates data and metadata management into independent server | ||
24 | clusters, similar to Lustre. Unlike Lustre, however, metadata and | ||
25 | storage nodes run entirely as user space daemons. Storage nodes | ||
26 | utilize btrfs to store data objects, leveraging its advanced features | ||
27 | (checksumming, metadata replication, etc.). File data is striped | ||
28 | across storage nodes in large chunks to distribute workload and | ||
29 | facilitate high throughputs. When storage nodes fail, data is | ||
30 | re-replicated in a distributed fashion by the storage nodes themselves | ||
31 | (with some minimal coordination from a cluster monitor), making the | ||
32 | system extremely efficient and scalable. | ||
33 | |||
34 | Metadata servers effectively form a large, consistent, distributed | ||
35 | in-memory cache above the file namespace that is extremely scalable, | ||
36 | dynamically redistributes metadata in response to workload changes, | ||
37 | and can tolerate arbitrary (well, non-Byzantine) node failures. The | ||
38 | metadata server takes a somewhat unconventional approach to metadata | ||
39 | storage to significantly improve performance for common workloads. In | ||
40 | particular, inodes with only a single link are embedded in | ||
41 | directories, allowing entire directories of dentries and inodes to be | ||
42 | loaded into its cache with a single I/O operation. The contents of | ||
43 | extremely large directories can be fragmented and managed by | ||
44 | independent metadata servers, allowing scalable concurrent access. | ||
45 | |||
46 | The system offers automatic data rebalancing/migration when scaling | ||
47 | from a small cluster of just a few nodes to many hundreds, without | ||
48 | requiring an administrator carve the data set into static volumes or | ||
49 | go through the tedious process of migrating data between servers. | ||
50 | When the file system approaches full, new nodes can be easily added | ||
51 | and things will "just work." | ||
52 | |||
53 | Ceph includes flexible snapshot mechanism that allows a user to create | ||
54 | a snapshot on any subdirectory (and its nested contents) in the | ||
55 | system. Snapshot creation and deletion are as simple as 'mkdir | ||
56 | .snap/foo' and 'rmdir .snap/foo'. | ||
57 | |||
58 | Ceph also provides some recursive accounting on directories for nested | ||
59 | files and bytes. That is, a 'getfattr -d foo' on any directory in the | ||
60 | system will reveal the total number of nested regular files and | ||
61 | subdirectories, and a summation of all nested file sizes. This makes | ||
62 | the identification of large disk space consumers relatively quick, as | ||
63 | no 'du' or similar recursive scan of the file system is required. | ||
64 | |||
65 | |||
66 | Mount Syntax | ||
67 | ============ | ||
68 | |||
69 | The basic mount syntax is: | ||
70 | |||
71 | # mount -t ceph monip[:port][,monip2[:port]...]:/[subdir] mnt | ||
72 | |||
73 | You only need to specify a single monitor, as the client will get the | ||
74 | full list when it connects. (However, if the monitor you specify | ||
75 | happens to be down, the mount won't succeed.) The port can be left | ||
76 | off if the monitor is using the default. So if the monitor is at | ||
77 | 1.2.3.4, | ||
78 | |||
79 | # mount -t ceph 1.2.3.4:/ /mnt/ceph | ||
80 | |||
81 | is sufficient. If /sbin/mount.ceph is installed, a hostname can be | ||
82 | used instead of an IP address. | ||
83 | |||
84 | |||
85 | |||
86 | Mount Options | ||
87 | ============= | ||
88 | |||
89 | ip=A.B.C.D[:N] | ||
90 | Specify the IP and/or port the client should bind to locally. | ||
91 | There is normally not much reason to do this. If the IP is not | ||
92 | specified, the client's IP address is determined by looking at the | ||
93 | address it's connection to the monitor originates from. | ||
94 | |||
95 | wsize=X | ||
96 | Specify the maximum write size in bytes. By default there is no | ||
97 | maximu. Ceph will normally size writes based on the file stripe | ||
98 | size. | ||
99 | |||
100 | rsize=X | ||
101 | Specify the maximum readahead. | ||
102 | |||
103 | mount_timeout=X | ||
104 | Specify the timeout value for mount (in seconds), in the case | ||
105 | of a non-responsive Ceph file system. The default is 30 | ||
106 | seconds. | ||
107 | |||
108 | rbytes | ||
109 | When stat() is called on a directory, set st_size to 'rbytes', | ||
110 | the summation of file sizes over all files nested beneath that | ||
111 | directory. This is the default. | ||
112 | |||
113 | norbytes | ||
114 | When stat() is called on a directory, set st_size to the | ||
115 | number of entries in that directory. | ||
116 | |||
117 | nocrc | ||
118 | Disable CRC32C calculation for data writes. If set, the OSD | ||
119 | must rely on TCP's error correction to detect data corruption | ||
120 | in the data payload. | ||
121 | |||
122 | noasyncreaddir | ||
123 | Disable client's use its local cache to satisfy readdir | ||
124 | requests. (This does not change correctness; the client uses | ||
125 | cached metadata only when a lease or capability ensures it is | ||
126 | valid.) | ||
127 | |||
128 | |||
129 | More Information | ||
130 | ================ | ||
131 | |||
132 | For more information on Ceph, see the home page at | ||
133 | http://ceph.newdream.net/ | ||
134 | |||
135 | The Linux kernel client source tree is available at | ||
136 | git://ceph.newdream.net/linux-ceph-client.git | ||
137 | |||
138 | and the source for the full system is at | ||
139 | git://ceph.newdream.net/ceph.git | ||
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 35c9b51d20ea..dd5806f4fcc4 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt | |||
@@ -291,6 +291,7 @@ Code Seq#(hex) Include File Comments | |||
291 | 0x92 00-0F drivers/usb/mon/mon_bin.c | 291 | 0x92 00-0F drivers/usb/mon/mon_bin.c |
292 | 0x93 60-7F linux/auto_fs.h | 292 | 0x93 60-7F linux/auto_fs.h |
293 | 0x94 all fs/btrfs/ioctl.h | 293 | 0x94 all fs/btrfs/ioctl.h |
294 | 0x97 00-7F fs/ceph/ioctl.h Ceph file system | ||
294 | 0x99 00-0F 537-Addinboard driver | 295 | 0x99 00-0F 537-Addinboard driver |
295 | <mailto:buk@buks.ipn.de> | 296 | <mailto:buk@buks.ipn.de> |
296 | 0xA0 all linux/sdp/sdp.h Industrial Device Project | 297 | 0xA0 all linux/sdp/sdp.h Industrial Device Project |