Lines Matching +full:d +full:- +full:cache +full:- +full:block +full:- +full:size
1 .. SPDX-License-Identifier: GPL-2.0
18 set using tune2fs(8). Kernel-determined defaults are indicated by (*).
27 dax Use direct access (no page cache). See
34 errors=remount-ro Remount the filesystem read-only on an error.
40 nouid32 Use 16-bit UIDs and GIDs.
42 oldalloc Enable the old block allocator. Orlov should
43 have better performance, we'd like to get some
45 orlov (*) Use the Orlov block allocator.
84 ------
87 a fixed size, of 1024, 2048 or 4096 bytes (8192 bytes on Alpha systems),
90 and also impose other limits on the size of files and the filesystem.
92 Block Groups
93 ------------
95 Blocks are clustered into block groups in order to reduce fragmentation
97 of consecutive data. Information about each block group is kept in a
98 descriptor table stored in the block(s) immediately after the superblock.
99 Two blocks near the start of each group are reserved for the block usage
101 are in use. Since each bitmap is limited to a single block, this means
102 that the maximum size of a block group is 8 times the size of a block.
104 The block(s) following the bitmaps in each block group are designated
105 as the inode table for that block group and the remainder are the data
106 blocks. The block allocation algorithm attempts to allocate data blocks
107 in the same block group as the inode which contains them.
110 --------------
116 the superblock are stored in block groups throughout the filesystem.
118 every block group, along with backups of the group descriptor block(s).
126 how many inodes and blocks are in each block group, when the filesystem
132 such as a volume name, a unique identification number, the inode size,
140 ------
147 group, flags, size, number of blocks used, access time, change time,
154 bits of the file size if the inode is a regular file (allowing file sizes
163 in the inode. There is a pointer to an indirect block (which contains
164 pointers to the next set of blocks), a pointer to a doubly-indirect
165 block (which contains pointers to indirect blocks) and a pointer to a
166 trebly-indirect block (which contains pointers to doubly-indirect blocks).
168 The flags field contains some ext2-specific flags which aren't catered
171 behaviour on a per-file basis. There are flags for secure deletion,
172 undeletable, compression, synchronous updates, immutability, append-only,
173 dumpable, no-atime, indexed directories, and data-journaling. Not all
177 -----------
188 block group as the directory in which they are first created.
190 The current implementation of ext2 uses a singly-linked list to store
198 -------------
205 block for the symlink, and most symlinks are less than 60 characters long.
207 Character and block special devices never have data blocks assigned to
212 --------------
215 for a particular user (normally the super-user). This is intended to
216 allow for the system to continue functioning even if non-privileged users
222 ----------------
233 ---------------------
240 revision 1. There are three 32-bit fields, one for compatible features
241 (COMPAT), one for read-only compatible (RO_COMPAT) features and one for
247 but the on-disk format is 100% compatible with older on-disk formats, so
257 An RO_COMPAT flag indicates that the on-disk format is 100% compatible
258 with older on-disk formats for reading (i.e. the feature does not change
259 the visible on-disk format). However, an old kernel writing to such a
268 An INCOMPAT flag indicates the on-disk format has changed in some
273 The COMPRESSION flag is an obvious INCOMPAT flag - if the kernel
290 --------
300 - per-file if you have the program source: use the O_SYNC flag to open()
301 - per-file if you don't have the source: use "chattr +S" on the file
302 - per-filesystem: add the "sync" option to mount (or in /etc/fstab)
308 -----------
310 There are various limits imposed by the on-disk layout of ext2. Other
313 created, and depend upon the block size chosen. The ratio of inodes to
315 increase the number of inodes is to increase the size of the filesystem.
318 Most of these limits could be overcome with slight changes in the on-disk
323 Filesystem block size 1kB 2kB 4kB 8kB
325 File size limit 16GB 256GB 2048GB 2048GB
326 Filesystem size limit 2047GB 8192GB 16384GB 32768GB
329 There is a 2.4 kernel limit of 2048GB for a single block device, so no
331 an upper limit on the block size imposed by the page size of the kernel,
337 There is a "soft" upper limit of about 10-15k files in a single directory
338 with the current linear linked-list directory implementation. This limit
341 (under development) allows 100k-1M+ files in a single directory without
342 performance problems (although RAM size becomes an issue at this point).
345 (imposed by the file size, the realistic limit is obviously much less)
347 enough 4-character names to make up unique directory entries, so they
352 ----------
357 to the on-disk ext2 layout. In a nutshell, the journal is a regular
394 RISC OS client http://www.esw-heim.tu-clausthal.de/~marco/smorbrod/IscaFS/