pmempool-transform - NVML man page

NAME
SYNOPSIS
DESCRIPTION
EXAMPLES
SEE ALSO

NAME

pmempool-transform – Modify internal structure of a pool set.

SYNOPSIS

pmempool transform [options] <poolset_file_src> <poolset_file_dst>

DESCRIPTION

The pmempool transform command modifies internal structure of a pool set defined by the poolset_file_src file, according to a structure described in the poolset_file_dst file.

The following operations are supported:

Currently these operations are allowed only for pmemobj pools (see libpmemobj(3)).

The poolset_file_src argument provides the source pool set to be changed.

The poolset_file_dst argument points to the target pool set.

When adding or deleting replicas, the two pool set files can differ only in the definitions of replicas which are to be added or deleted. One cannot add and remove replicas in the same step. Only one of these operations can be performed at a time. Reordering replicas can be combined with any of them. Also, to add a replica it is necessary for its effective size to match or exceed the pool size. Otherwise the whole operation fails and no changes are applied. Effective size of a replica is the sum of sizes of all its part files decreased by 4096 bytes per each part file. The 4096 bytes of each part file is utilized for storing internal metadata of the pool part files.

Available options:
-d, --dry-run

Enable dry run mode. In this mode no changes are applied, only check for viability of the operation is performed.

-v, --verbose

Increase verbosity level.

-h, --help

Display help message and exit.

EXAMPLES

Example 1.

Let files /path/poolset_file_src and /path/poolset_file_dst have the following contents:

PMEMPOOLSET
20M /0/partfile1
20M /0/partfile2
25M /0/partfile3
REPLICA
40M /1/partfile1
20M /1/partfile2
PMEMPOOLSET
20M /0/partfile1
20M /0/partfile2
25M /0/partfile3
REPLICA
40M /1/partfile1
20M /1/partfile2
REPLICA
50M /2/partfile1
20M /2/partfile2

Then, the command

pmempool transform /path/poolset_file_src /path/poolset_file_dst

adds a replica to the pool set. All other replicas remain unchanged and the size of the pool remains 60M.

Example 2.

Let files /path/poolset_file_src and /path/poolset_file_dst have the following contents:

PMEMPOOLSET
20M /0/partfile1
20M /0/partfile2
25M /0/partfile3
REPLICA
40M /1/partfile1
20M /1/partfile2
PMEMPOOLSET
20M /0/partfile1
20M /0/partfile2
25M /0/partfile3

Then

pmempool_transform /path/poolset_file_src /path/poolset_file_dst

deletes the second replica from the pool set. The first replica remains unchanged and the size of the pool is still 60M.

SEE ALSO

libpmempool(3), libpmemblk(3), libpmemlog(3), pmempool(1)