Low Disk Space

Mike Phillips -

ClustrixDB stores database data in the /data/clustrix/device1 file on each node. The undo log for each node is also stored in this file.
You can read more about the undo log in ClustrixDB in our docs here: Concurrency Control - Version History and Garbage Collection.
When data is deleted from the cluster or undo log is freed, the space  becomes available to the database, but the device1 file does not shrink. This is similar to how MySQL stores data, as described here: How to shrink/purge ibdata1 file in MySQL.
As ClustrixDB is a distributed database instead of a single instance, having the option to store each table or database in it's own file doesn't make as much sense.

You can use the command /opt/clustrix/bin/clx stat to see how much space is actually being used by the database.

Example:

[root@clustrix001 ~]# /opt/clustrix/bin/clx stat
Cluster Name:    cl943e5fc8a333ee99
Cluster Version: 5.0.45-clustrix-v7.0.1
Cluster Status:   OK 
Cluster Size:    3 nodes
Current Node:    clustrix001 - nid 1

nid |   Hostname  | Status |  IP Address | TPS |       Used      | Total
----+-------------+--------+-------------+-----+-----------------+------
  1 | clustrix001 |    OK  |  10.1.10.41 |   1 |  562.9M (12.2%) |  4.5G
  2 | clustrix002 |    OK  |  10.1.10.42 |   0 |  562.8M (12.2%) |  4.5G
  3 | clustrix003 |    OK  |  10.1.10.43 |   0 |  562.8M (12.2%) |  4.5G
----+-------------+--------+-------------+-----+-----------------+------
                                             1 |    1.1G (12.2%) |  9.0G

We recommend that /data/clustrix/ and /data/clustrix/logs/ are on separate partitions. More on this recommendation is in our docs here: Best Practices for Platform Configuration of ClustrixDB Software Installations - Storage Configuration


There are a few options to increase the available disk space: 

  • SoftFail Each Node, Format to Reduce Device1 File Size

You can softfail each node before formatting it with:

ALTER CLUSTER SOFTFAIL <nodeid>;
  • Increase Disk Capacity for /data/clustrix/ partition

If you're able to increase the size of the partition that device1 is on, this would give additional headroom.

  • Add a New Node to the Cluster

A new node would act just like a formatted node with a smaller device1 file.

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