[lustre-discuss] Multiple Lustre filesystem

[Colin Faber]

The number of OST's is typically calculated based on overall OST size
(cannot exceed maximum FS limits), and performance. The number you choose
to utilize should be based on that, if that means you get the best
performance out of your system with fewer OST's which are larger then use
that. In any case benchmarking of your hardware should be a first step
before deciding layouts.

Secondly the number of MDTs required is also based on performance and file
limit considerations. A single MDT is required, however multiple MDT's can
be utilized on the same file system (via DNE feature) to allow you to
horizontally scale your metadata performance, as well as total file system
file count capacity.

-cf


On Fri, Sep 15, 2017 at 10:20 AM, Ravi Konila <ravibhatk at gmail.com> wrote:

> Hi
> Thank you very much for quick response.
>
> Just a quick questions, some times I do get confused.
>
> 1. If I need 78TB for home and 50TB for scratch, how many OSTs should be
> there for each file system in a single DAS (attached to two OSSs (HA).
> Presently my OST table is as follows:
>
>     Total HDD RAID 6 Overhead Available HDD each HDD Capacity (in TB) Total
> in TB)
> OST_01   20 2 18 1.2 21.6
> OST_02   20 2 18 1.2 21.6
> OST_03   20 2 18 1.2 21.6
> OST_04   20 2 18 1.2 21.6
> OST_05   20 2 18 1.2 21.6
> OST_06   20 2 18 1.2 21.6
>             129.6
>
> 2. How many MDTs should I create for each file system?
>
> Regards
>
> *Ravi Konila*
> Sr. Technical Consultant
> MSIL, India
> Ph: +91 9901072688
>
>
> *From:* Colin Faber
> *Sent:* Friday, September 15, 2017 8:18 PM
> *To:* Ravi Konila
> *Cc:* Lustre Discuss
> *Subject:* Re: [lustre-discuss] Multiple Lustre filesystem
>
> Hi,
>
> On Fri, Sep 15, 2017 at 6:54 AM, Ravi Konila <ravibhatk at gmail.com> wrote:
>
>> Hi,
>>
>> I have few queries about Lustre File system as I am building new Lustre
>> File system for our production use.
>>
>> 1. Can I create more than one Lustre file system for example, one Lustre
>> file system for /home and other for /scratch ?
>>
>
> Yes
>
>
>> 2. As of now I have created 6 OSTs (total of 128TB storage) under shared
>> storage which uses two OSSs, how do I allocate that to different Lustre
>> file system if I can create multiple file system?
>>
>
> You will need to partition the storage and assign each storage target to a
> different file system name.
>
>
>> 3. With single MDT can I have multiple Lustre file system?
>>
>
> No
>
>
>> 4. Is it better to create multiple MDTs or single MDT would do? (again I
>> am using single shared storage with 2 MDS/MGS)?
>>
>
> You can have 1 MGS for multiple file systems, but each file system
> requires it's own MDT, and each file system can have multiple MDT's via DNE
> feature.
>
>
>>
>> Any help in this regard would be highly appreciated.
>>
>> *Ravi Konila*
>> Sr. Technical Consultant
>> MSIL, India
>> Ph: +91 9901072688
>>
>>
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>
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