[LU-1521] What's the "best" default stripe count

• Type: Task
• Resolution: Fixed
• Priority: Minor
• Affects Version/s: Lustre 2.2.0
• Labels: lustre stripe

Environment

MDS HW
----------------------------------------------------------------------------------------------------
Linux XXXX.admin.cscs.ch 2.6.32-220.7.1.el6_lustre.g9c8f747.x86_64
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 16
Vendor ID: AuthenticAMD
CPU family: 16
64Gb RAM
Interconnect IB 40Gb/s

MDT LSI 5480 Pikes Peak
SSDs SLC
----------------------------------------------------------------------------------------------------

OSS HW
----------------------------------------------------------------------------------------------------
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 32
Vendor ID: GenuineIntel
CPU family: 6
64Gb RAM
Interconnect IB 40Gb/s

OST LSI 7900
----------------------------------------------------------------------------------------------------

Router nodes
-------------------
12 router nodes - IB 40Gb/s

Clients
---------
Cray XE6 - Lustre 1.8.6



1 MDS + 1 fail over
12 OSS - 6 OST per OSS

• Assignee: Cliff White (Inactive)
• Reporter: Fabio Verzelloni

Description

Dear support,
I'd like to know if there's a kind of "best practice" regarding the default stripe count to set on the Lustre file system.
I noticed that, based on the hardware we are using, having a stripe count to 24 often create problem simply untaring a file, instead having a stripe count to 4 seems to improve the situation.

Do you have any suggestion of how to understand what's best stripe count to set and how to suggest to our users how to deal with that?

Thanks
Fabio

Comments

[Cliff White (Inactive)]

Question answered

[Fabio Verzelloni]

Hello Cliff,
yes, feel free to close the ticket.

Regards
Fabio

[Cliff White (Inactive)]

Can we close this issue, or are there further questions?

[Cliff White (Inactive)]

The 'best' stripe count is very much application-dependent. So, you really must test your applications and decide what is best for your individual case.
Fortunately, you can test different stripe counts simply by using different output directories. Remember also that the stripe count determines the number of parallel IOs a client will issue. So, the IO size required by the application, the clients network capacity and the server's ability to sink IO all affect the choice of stripe. Hope this helps.