---
title:  Disk Store File Names and Extensions
---

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Disk store files include store management files, access control files, and the operation log, or oplog, files, consisting of one file for deletions and another for all other operations.

<a id="file_names_and_extensions__section_AE90870A7BDB425B93111D1A6E166874"></a>
The next tables describe file names and extensions; they are followed by example disk store files.

## <a id="file_names_and_extensions__section_C99ABFDB1AEA4FE4B38F5D4F1D612F71" class="no-quick-link"></a>File Names

File names have three parts: usage identifier, disk store name, and oplog sequence number.

**First Part of File Name: Usage Identifier**

| Values   | Used for                                                               | Examples                                   |
|----------|------------------------------------------------------------------------|--------------------------------------------|
| OVERFLOW | Oplog data from overflow regions and queues only.                      | OVERFLOWoverflowDS1\_1.crf                 |
| BACKUP   | Oplog data from persistent and persistent+overflow regions and queues. | BACKUPoverflowDS1.if, BACKUPDEFAULT.if     |
| DRLK\_IF | Access control - locking the disk store.                               | DRLK\_IFoverflowDS1.lk, DRLK\_IFDEFAULT.lk |

**Second Part of File Name: Disk Store Name**

| Values                  | Used for                                                                                                                  | Examples                                                                             |
|-------------------------|---------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------|
| &lt;disk store name&gt; | Non-default disk stores.                                                                                                  | name="overflowDS1" DRLK\_IFoverflowDS1.lk, name="persistDS1" BACKUPpersistDS1\_1.crf |
| DEFAULT                 | Default disk store name, used when persistence or overflow are specified on a region or queue but no disk store is named. | DRLK\_IFDEFAULT.lk, BACKUPDEFAULT\_1.crf                                             |

**Third Part of File Name: oplog Sequence Number**

| Values                            | Used for                                        | Examples                                                                     |
|-----------------------------------|-------------------------------------------------|------------------------------------------------------------------------------|
| Sequence number in the format \_n | Oplog data files only. Numbering starts with 1. | OVERFLOWoverflowDS1\_1.crf, BACKUPpersistDS1\_2.crf, BACKUPpersistDS1\_3.crf |

## <a id="file_names_and_extensions__section_4FC89D10D6304088882B2E278A889A9B" class="no-quick-link"></a>File Extensions

| File extension | Used for                                         | Notes                                                                                                |
|----------------|--------------------------------------------------|------------------------------------------------------------------------------------------------------|
| if             | Disk store metadata                              | Stored in the first disk-dir listed for the store. Negligible size - not considered in size control. |
| lk             | Disk store access control                        | Stored in the first disk-dir listed for the store. Negligible size - not considered in size control. |
| crf            | Oplog: create, update, and invalidate operations | Pre-allocated 90% of the total max-oplog-size at creation.                                           |
| drf            | Oplog: delete operations                         | Pre-allocated 10% of the total max-oplog-size at creation.                                           |
| krf            | Oplog: key and crf offset information            | Created after the oplog has reached the max-oplog-size. Used to improve performance at startup.      |

Example files for disk stores persistDS1 and overflowDS1:

``` pre
bash-2.05$ ls -tlr persistData1/
total 8
-rw-rw-r--   1 person users        188 Mar  4 06:17 BACKUPpersistDS1.if
-rw-rw-r--   1 person users          0 Mar  4 06:18 BACKUPpersistDS1_1.drf
-rw-rw-r--   1 person users         38 Mar  4 06:18 BACKUPpersistDS1_1.crf
 
bash-2.05$ ls -tlr overflowData1/
total 1028
-rw-rw-r--   1 person users          0 Mar  4 06:21 DRLK_IFoverflowDS1.lk
-rw-rw-r--   1 person users          0 Mar  4 06:21 BACKUPoverflowDS1.if
-rw-rw-r--   1 person users 1073741824 Mar  4 06:21 OVERFLOWoverflowDS1_1.crf
```

Example default disk store files for a persistent region:

``` pre
bash-2.05$ ls -tlr
total 106
-rw-rw-r--   1 person users       1010 Mar  8 15:01 defTest.xml
drwxrwxr-x   2 person users        512 Mar  8 15:01 backupDirectory
-rw-rw-r--   1 person users          0 Mar  8 15:01 DRLK_IFDEFAULT.lk
-rw-rw-r--   1 person users  107374183 Mar  8 15:01 BACKUPDEFAULT_1.drf
-rw-rw-r--   1 person users  966367641 Mar  8 15:01 BACKUPDEFAULT_1.crf
-rw-rw-r--   1 person users        172 Mar  8 15:01 BACKUPDEFAULT.if
```
