Hi Allessandra,
Yep, we've certainly been offered this as a workable solution. To
clarify, this is a 4U server, with 12 bays on the rear and 24 on the
front; the DPM storage would be hosted on a single raid card (all 36
bays!) and the two (RAID 1) system disks would be directly attached to
the motherboard, which appears to have capacity for 6 SATA devices.
Cheers,
Mike
On 7 June 2010 22:14, Alessandra Forti <[log in to unmask]> wrote:
> Hi Mike,
>
>> As Brian suggests, we are likely to host the system disks on the
>> motherboard disk controller, rather than the RAID card. This frees up
>> 2 bays and means we have to buy one less server (16 rather than 17)
>> for the ~same total storage capacity.
>
>
> I was told by the vendor this is not possible. Unless we are talking of two
> different storage units. If you say it is possible I'll ask again, perhaps I
> misunderstood.
>
> cheers
> alessandra
>
> Mike Kenyon wrote:
>>
>> Hi All,
>>
>> Thanks for the input thus far.
>>
>> From what we can tell, the 36-bay solution we've been offered has two
>> SAS backplanes, one with 12 bays, the other with 24. Quite how these
>> are connected to the RAID card isn't entirely clear to us yet, though
>> we have theories.
>>
>> We understand that the bandwidth-per-disk to one of the backplanes
>> (paradoxically the 12-bay one, it seems) will be less than to the
>> other, though we're seeking confirmation of this.
>>
>> As Brian suggests, we are likely to host the system disks on the
>> motherboard disk controller, rather than the RAID card. This frees up
>> 2 bays and means we have to buy one less server (16 rather than 17)
>> for the ~same total storage capacity.
>>
>> Cheers,
>> Mike.
>>
>>
>> On 4 June 2010 15:40, Alessandra Forti <[log in to unmask]> wrote:
>>
>>>>
>>>> Not have the system disk connected through the raid. Ie only use raid
>>>> cards for data parttions/filesystems.
>>>>
>>>
>>> not on these units.
>>>
>>> [log in to unmask] wrote:
>>>
>>>>
>>>> Other things you might tweant to consider are:
>>>> Splitting into two separate raids.
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: GRIDPP2: Deployment and support of SRM and local storage
>>>> management [mailto:[log in to unmask]] On Behalf Of
>>>> Alessandra Forti
>>>> Sent: 04 June 2010 12:12
>>>> To: [log in to unmask]
>>>> Subject: Re: 36-bay storage nodes
>>>>
>>>> Hi Mike,
>>>>
>>>> They are in use at CERN since January. Manchester just bought them but
>>>> we don't have them on site yet. The usable space is 30x2TB(3x2TB for the
>>>> raid) + 2 slots for the OS. Beyond that the raid card efficiency
>>>> degrades according to the vendor.
>>>>
>>>> cheers
>>>> alessandra
>>>>
>>>> Mike Kenyon wrote:
>>>>
>>>>
>>>>>
>>>>> Hi All,
>>>>>
>>>>> As most of you probably know, we're going through the procurement
>>>>> process
>>>>> at Glasgow, and are looking to buy ~1TB of disk.
>>>>>
>>>>> One solution we've been offered uses a 36-bay server (yes, that'd be
>>>>> 36 x 2TB disks per server). Does anyone out there have experience of
>>>>> these beasts? We're trying to figure out if they've been successfully
>>>>> (or
>>>>> otherwise) deployed within GridPP...clearly, suppliers will only
>>>>> mention
>>>>> favourable case studies.
>>>>>
>>>>>
>>>>> Cheers,
>>>>> Mike
>>>>>
>>>>>
>>>
>>> --
>>> The most effective way to do it, is to do it. (Amelia Earhart)
>>> Northgrid Tier2 Technical Coordinator
>>> http://www.hep.manchester.ac.uk/computing/tier2
>>>
>>>
>
> --
> The most effective way to do it, is to do it. (Amelia Earhart)
> Northgrid Tier2 Technical Coordinator
> http://www.hep.manchester.ac.uk/computing/tier2
>
>
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