[Lustre-discuss] Hardware Question

Aaron Knister aaron at iges.org
Wed Oct 17 08:29:41 PDT 2007


So if I have arrays with 15 drives in them should I just configure  
two smaller arrays? Also if I make a giant 30 terabyte filesystem of  
underlying say 6TB disk arrays and one of my disk arrays bites the  
dust what happens to the rest of the filesystem and how easy is it to  
recover from this situation?

-Aaron

On Oct 10, 2007, at 11:48 AM, Andreas Dilger wrote:

> On Oct 10, 2007  09:40 -0600, Lundgren, Andrew wrote:
>> As RH 5.1 will support 16TB ext3 partitions, will lustre inherit that
>> functionality?
>
> We haven't looked at this yet.  The ldiskfs code is ext3 + patches,  
> so there
> is some chance that it will work (more likely on 64-bit platforms),  
> but
> we haven't audited the ldiskfs patches to check if they are 32-bit  
> clean.
>
>>> -----Original Message-----
>>> From: lustre-discuss-bounces at clusterfs.com
>>> [mailto:lustre-discuss-bounces at clusterfs.com] On Behalf Of
>>> Andreas Dilger
>>> Sent: Wednesday, October 10, 2007 9:26 AM
>>> To: Aaron Knister
>>> Cc: lustre-discuss at clusterfs.com
>>> Subject: Re: [Lustre-discuss] Hardware Question
>>>
>>> On Oct 06, 2007  10:28 -0400, Aaron Knister wrote:
>>>> Oh, right I forgot about that. Well...if i had an 8tb lun
>>> and split it
>>>> into 2 volume groups using LVM do you think the performance
>>> would be
>>>> worse than making 2 raids at the hardware level?
>>>
>>> Well, it won't be doing the disks any favours, since you'll
>>> now have contention between the OSTs, and the kernel will be
>>> doing a poor job with the IO elevator decisions.  I would
>>> suggest making 2 smaller RAID LUNs instead.
>>>
>>> In the end it is up to you to decide if the IO performance is
>>> acceptable.
>>> You can do some testing using lustre-iokit to see what the
>>> component device performance is.
>>>
>>>> On Oct 5, 2007, at 6:18 PM, Andreas Dilger wrote:
>>>>
>>>>> On Oct 05, 2007  13:14 -0400, Aaron Knister wrote:
>>>>>> Make that 6x 9.7TB luns.
>>>>>
>>>>> Lustre (== ext3) doesn't support >= 8TB LUNs.
>
> Cheers, Andreas
> --
> Andreas Dilger
> Principal Software Engineer
> Cluster File Systems, Inc.
>

Aaron Knister
Associate Systems Administrator/Web Designer
Center for Research on Environment and Water

(301) 595-7001
aaron at iges.org



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