Adjusting the read buffer for FlashBackup and FlashBackup-Windows

Use the following procedures to adjust the read buffer for NetBackup FlashBackup and FlashBackup-Windows raw partition backups.

To adjust the FlashBackup read buffer for UNIX and Linux clients

Create the following touch file on each client:
```
/usr/openv/netbackup/FBU_READBLKS
```
Enter the values in the FBU_READBLKS file, as follows.
On the first line of the file: enter an integer value for the read buffer size in blocks for full backups and/or for incremental backups. The defaults are 256 blocks (131072 bytes, or 128 KB) during full backups and 64 blocks (32768 bytes, or 32 KB) for incremental backups. The block size is equal to (KB size * 2), or (Number of bytes/512).
To change both values, separate them with a space.
For example:
```
512 128
```
This entry sets the full backup read buffer to 256 KB and the incremental read buffer to 64 KB.
You can use the second line of the file to set the tape record write size, also in blocks. The default is the same size as the read buffer. The first entry on the second line sets the full backup write buffer size. The second value sets the incremental backup write buffer size. To set read buffer size and tape record write size to the same values, the file would read altogether as:
```
512 128
512 128
```

To adjust the FlashBackup-Windows read buffer for Windows clients

Click Host Properties > Clients, right-click on the client and select Properties.
Click Windows Client > Client Settings.
For Raw partition read buffer size, specify the size of the read buffer.
A read buffer size larger than the 32 KB default may increase backup speed. Results vary from one system to another; experimentation may be required. A setting of 1024 may be a good starting point.
Note the following:
- This setting applies to raw partition backups as well as to FlashBackup-Windows policies (including NetBackup for VMware).
- This setting applies to full backups and to incremental backups.