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SYMAJ's avatar
SYMAJ
Level 6
12 years ago

5220 Appliances - Buffer Tuning & Throughput

Does anyone have any experience of tuning throughput on a 5220 Appliance ? I note that the data buffers are set to 262144 (standard setting) and there are 30 of them.  Are you finding that these re...
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  • Mark_Solutions's avatar
    Mark_Solutions
    12 years ago

    You can change the buffer sizes from the CLISH (or drop into the O/S and add the usual touch files)

    I would set the SIZE_DATA_BUFFERS to 256kb (262144) but when doing this also set the SIZE_DATA_BUFFERS_DISK to what ever value you want (1048576 usually works OK), otherwise they will both use this setting - same goes for the number of buffers.

    You can enable and disable compression when ever you like - but I would start with it disabled and see how it goes.

    The 2.5.1b update is identical to the 2.5.1 update - only the installer has changed so you can take into account any feedback that has already been provided from that one so far.

    Hope this helps

Nicolai's avatar
Nicolai
Moderator
12 years ago

In general  when writing to tape you should use a 256K block size and at least 128 buffers.

Just demonstrate what difference it does it did this test when LTO3 has hot. 

Before tuning: 19MB/sec (default values)

Second tuning attempt: 49MB/sec (using 128K block size, 64 buffers)

Final result: 129MB/sec  (using 128K block size and 256 buffers)

Since it's a LOT3 drive have a native transfer rate of 80MB/sec any further tuning attempt are meaningless.