Ploop/Limits - Revision history

Sergey Bronnikov: Marked this version for translation

2015-12-25T22:31:50Z

Marked this version for translation

Sergey Bronnikov: add 'translate' tags

2015-12-25T22:31:08Z

add 'translate' tags

Kir: Kir moved page Ploop/limits to Ploop/Limits

2014-07-30T01:14:16Z

Kir moved page Ploop/limits to Ploop/Limits

Kir: explained ext4 fs limit

2014-07-30T01:11:50Z

explained ext4 fs limit

Kir: 2^32, ploop v2 limit explained

2014-07-30T01:03:41Z

2^32, ploop v2 limit explained

Kir: fix ploop v2 size in PB

2014-07-30T00:52:41Z

fix ploop v2 size in PB

Kir: created

2014-07-30T00:41:00Z

created

New page

[[Ploop]] images has the following limits:

* Number of snapshots: 126
* Image size:
** ploop v1: 2 TB minus 1 MB
** ploop v2: 2 PB (4096 TB) minus 1 MB
* Inner ext4 file system size: currently set to 16 TB

== Conversion ==

Use ploop convert tool to convert from ploop v1 to ploop v2 image.

== Internals ==

Ploop v1 image size limitation comes from the fact that unsigned 32 bit integer
is used to store sector address inside the ploop image. Therefore the maximum
number of sectors is (u32)-1, which is 4294967295. As sector size is 512 bytes,
4294967295 sectors are equal to 2 terabytes. From that number, we should subtract
1 megabyte, as first 1MB of image is used for translation table.

@@ Line 1: / Line 1: @@
 <translate>
 [[Ploop]] images has the following limits:
 * Number of snapshots: 126
 * Image size:
@@ Line 8: / Line 10: @@
 * Inner ext4 file system size: currently set to 16 TB
-== Conversion ==
+== Conversion == <!--T:3-->
 Use ploop convert tool to convert from ploop v1 to ploop v2 image.
-== Internals ==
+== Internals == <!--T:5-->
-=== Image size limit ===
+=== Image size limit === <!--T:6-->
 Ploop v1 image size limitation comes from the fact that unsigned 32 bit integer
 is used to store sector address inside the ploop image. Therefore the maximum
@@ Line 22: / Line 26: @@
 used for header and L2 translation table, maximum image size is decreased by 1MB.
 Ploop v2 uses the same unsigned 32 bit field to address blocks rather than sectors.
 Block size itself is measured in 512 byte sectors, and can be specified during image creation.
@@ Line 29: / Line 34: @@
 used for header and L2 translation table, maximum image size is decreased by 1MB.
-=== Filesystem size limit ===
+=== Filesystem size limit === <!--T:9-->
 Currently ext4 file system is used. An ability to resize ext4 is limited by
 its block group descriptor table, which size can be specified during file

@@ Line 1: / Line 1: @@
 [[Ploop]] images has the following limits:
@@ Line 35: / Line 36: @@
 Currently ploop library hardcodes this value so that filesystem can be resized
 up to 16 TB of space.

@@ Line 12: / Line 12: @@
 == Internals ==
 Ploop v1 image size limitation comes from the fact that unsigned 32 bit integer
@@ Line 25: / Line 27: @@
 Same as with ploop v1, the first megabyte of the image is
 used for header and L2 translation table, maximum image size is decreased by 1MB.

← Older revision	Revision as of 01:14, 30 July 2014
(No difference)

@@ Line 10: / Line 10: @@
 Use ploop convert tool to convert from ploop v1 to ploop v2 image.
 == Internals ==
@@ Line 16: / Line 15: @@
 Ploop v1 image size limitation comes from the fact that unsigned 32 bit integer
 is used to store sector address inside the ploop image. Therefore the maximum
-number of sectors is (u32)-1, which is 4294967295. As sector size is 512 bytes,
+number of sectors is 2<sup>32</sup>, which is 4294967295. As sector size is 512 bytes,
-4294967295 sectors are equal to 2 terabytes. From that number, we should subtract
+4294967295 sectors are equal to 2 terabytes. As the first megabyte of the image is
-megabyte, as first 1MB of image is used for translation table.
+used for header and L2 translation table, maximum image size is decreased by 1MB.

@@ Line 4: / Line 4: @@
 * Image size:
 ** ploop v1: 2 TB minus 1 MB
-** ploop v2: 2 PB (4096 TB) minus 1 MB
+** ploop v2: 4 PB (4096 TB) minus 1 MB
 * Inner ext4 file system size: currently set to 16 TB