---
name: "pmempool-transform"
section: "1"
platform: "linux"
package: "pmdk-tools"
version: "1.13.1-1.1+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/pmempool-transform"
---

# pmempool-transform(1)

Modify internal structure of a pool set.

## NAME

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

## SYNOPSIS

-

  ```
  pmempool transform [options] <poolset_file_src> <poolset_file_dst>
  ```

## NOTE

NOTICE: The **libpmemblk** and **libpmemlog** libraries are deprecated since PMDK 1.13.0 release.

## 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:

- •

  adding replicas - one or more new replicas can be added and synchronized with other replicas in the pool set,

- •

  removing replicas - one or more replicas can be removed from the pool set ,

- •

  adding or removing pool set options.

Only one of the above operations can be performed at a time.

Currently adding and removing replicas are allowed only for **pmemobj** pools (see [**libpmemobj**(7)](/libpmemobj/7.md)).

The *poolset\_file\_src* argument provides the source pool set to be changed.

The *poolset\_file\_dst* argument points to the target pool set.

### 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

**[pmempool(1)](/pmempool/1.md)**, **[libpmemblk(7)](/libpmemblk/7.md)**, **[libpmemlog(7)](/libpmemlog/7.md)**, **[libpmempool(7)](/libpmempool/7.md)** and **\<https://pmem.io\>**