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| + | <translate> | ||
| + | <!--T:1--> | ||
Everything you wanted to know about DISKINODES for ploop but were afraid to ask. | Everything you wanted to know about DISKINODES for ploop but were afraid to ask. | ||
| − | == Limitations == | + | == Limitations == <!--T:2--> |
| + | <!--T:3--> | ||
With simfs layout, vzquota is used to set limits for DISKSPACE and | With simfs layout, vzquota is used to set limits for DISKSPACE and | ||
DISKINODES, so these limits can be changed any time. | DISKINODES, so these limits can be changed any time. | ||
| + | <!--T:4--> | ||
Unlike simfs, ploop contains a real file system, so amount of disk space | Unlike simfs, ploop contains a real file system, so amount of disk space | ||
and disk inodes are properties of the file system, determined while | and disk inodes are properties of the file system, determined while | ||
| Line 12: | Line 16: | ||
inodes. | inodes. | ||
| + | <!--T:5--> | ||
{{Note|There is no way to change DISKINODES for existing ploop. This is a limitation of ext4.}} | {{Note|There is no way to change DISKINODES for existing ploop. This is a limitation of ext4.}} | ||
| + | <!--T:6--> | ||
In other words, <code>vzctl set --diskinodes</code> is ignored for ploop layout -- it can only be specified on create. | In other words, <code>vzctl set --diskinodes</code> is ignored for ploop layout -- it can only be specified on create. | ||
| − | == Default value == | + | == Default value == <!--T:7--> |
| + | <!--T:8--> | ||
By default, ext4 allocates 1 (one) inode per each 16 KB of data; this is | By default, ext4 allocates 1 (one) inode per each 16 KB of data; this is | ||
practically the same as to assume that the average file size will be 16KB. | practically the same as to assume that the average file size will be 16KB. | ||
| + | <!--T:9--> | ||
For example, when creating a ploop with 40GB of disk space, 2621440 inodes | For example, when creating a ploop with 40GB of disk space, 2621440 inodes | ||
will be available: | will be available: | ||
| + | <!--T:10--> | ||
<math>\frac{40 * 1024 * 1024}{16} = 2621440</math> | <math>\frac{40 * 1024 * 1024}{16} = 2621440</math> | ||
| − | == Increasing == | + | == Increasing == <!--T:11--> |
| + | <!--T:12--> | ||
If the above default is too low for your usage (for example, a container | If the above default is too low for your usage (for example, a container | ||
has or will have too many small files), you can specify a larger value | has or will have too many small files), you can specify a larger value | ||
for DISKINODES '''during container creation or conversion only'''. | for DISKINODES '''during container creation or conversion only'''. | ||
| + | <!--T:13--> | ||
{{Note|The feature works since vzctl 4.7.}} | {{Note|The feature works since vzctl 4.7.}} | ||
| + | <!--T:14--> | ||
{{Note|You can only specify <code>--diskinodes</code> for <code>vzctl create</code> or <code>vzctl convert</code>.}} | {{Note|You can only specify <code>--diskinodes</code> for <code>vzctl create</code> or <code>vzctl convert</code>.}} | ||
| + | <!--T:15--> | ||
The way it works is the following. First, a file system big enough | The way it works is the following. First, a file system big enough | ||
to accommodate the requested number of DISKINODES is created, and then | to accommodate the requested number of DISKINODES is created, and then | ||
| Line 41: | Line 54: | ||
requested amount of DISKSPACE. | requested amount of DISKSPACE. | ||
| + | <!--T:16--> | ||
Example: | Example: | ||
| − | vzctl create 123 --diskspace 40G --diskinodes 5242880 | + | <!--T:17--> |
| − | + | vzctl create 123 --diskspace 40G --diskinodes 5242880 | |
| + | <!--T:18--> | ||
Here, a filesystem big enough to have 5242880 of diskinodes | Here, a filesystem big enough to have 5242880 of diskinodes | ||
will be created (it's 5242880 * 16K = 80G), then downsized to 40G. | will be created (it's 5242880 * 16K = 80G), then downsized to 40G. | ||
| − | == Issues == | + | == Issues == <!--T:19--> |
| − | === Too high DISKINODES value === | + | === Too high DISKINODES value === <!--T:20--> |
| + | <!--T:21--> | ||
Sometimes, when the amount of DISKINODES specified is too high, | Sometimes, when the amount of DISKINODES specified is too high, | ||
a very large filesystem is created, and it can not be downsized | a very large filesystem is created, and it can not be downsized | ||
| Line 58: | Line 74: | ||
shown when converting a container from simfs to ploop: | shown when converting a container from simfs to ploop: | ||
| − | vzctl set ''CTID'' --diskspace 40G --diskinodes 1000000000 --save | + | <!--T:22--> |
| + | vzctl set ''CTID'' --diskspace 40G --diskinodes 1000000000 --save | ||
... | ... | ||
vzctl convert ''CTID'' | vzctl convert ''CTID'' | ||
| Line 67: | Line 84: | ||
Failed to resize image: Error in ploop_resize_image (ploop.c:2477): Unable to change image size to 83877888 sectors, minimal size is 502423144 [38] | Failed to resize image: Error in ploop_resize_image (ploop.c:2477): Unable to change image size to 83877888 sectors, minimal size is 502423144 [38] | ||
| + | <!--T:23--> | ||
In this case, 1G inodes requirement leads to creation of 16TB filesystem | In this case, 1G inodes requirement leads to creation of 16TB filesystem | ||
(remember, 1 inode per 16K). Unfortunately, such huge FS can't be downsized | (remember, 1 inode per 16K). Unfortunately, such huge FS can't be downsized | ||
| Line 72: | Line 90: | ||
the error message are in sectors which are 512 bytes each). | the error message are in sectors which are 512 bytes each). | ||
| + | <!--T:24--> | ||
'''Solution 1''': please be reasonable when requesting diskinodes for ploop. | '''Solution 1''': please be reasonable when requesting diskinodes for ploop. | ||
| + | <!--T:25--> | ||
'''Solution 2''': please set DISKINODES to 0 before conversion: | '''Solution 2''': please set DISKINODES to 0 before conversion: | ||
| − | vzctl stop ''CTID'' | + | <!--T:26--> |
| + | vzctl stop ''CTID'' | ||
vzctl set ''CTID'' --diskspace ''xxx''G --diskinodes 0 --save | vzctl set ''CTID'' --diskspace ''xxx''G --diskinodes 0 --save | ||
vzctl convert ''CTID'' | vzctl convert ''CTID'' | ||
| + | <!--T:27--> | ||
This will lead to creating a filesystem with default number of inodes. | This will lead to creating a filesystem with default number of inodes. | ||
| − | === Too low DISKINODES value === | + | === Too low DISKINODES value === <!--T:28--> |
| + | <!--T:29--> | ||
If DISKINODES specified during <code>create</code> or <code>convert</code> is | If DISKINODES specified during <code>create</code> or <code>convert</code> is | ||
lower than the default (1 inode per 16K of disk space), it is silently ignored. | lower than the default (1 inode per 16K of disk space), it is silently ignored. | ||
In other words, there is no way to limit DISKINODES to lower than DISKSPACE / 16384. | In other words, there is no way to limit DISKINODES to lower than DISKSPACE / 16384. | ||
| − | == See also == | + | == See also == <!--T:30--> |
* {{git commit|vzctl|ef320d32a4}} | * {{git commit|vzctl|ef320d32a4}} | ||
* https://lists.openvz.org/pipermail/users/2014-October/005913.html | * https://lists.openvz.org/pipermail/users/2014-October/005913.html | ||
| + | </translate> | ||
[[Category: Storage]] | [[Category: Storage]] | ||