Re: What would a good OSD node hardware configuration look like?

[Wido den Hollander <wido@widodh.nl>]

On 07-11-12 09:17, Gandalf Corvotempesta wrote:
> 2012/11/7 Wido den Hollander <wido@widodh.nl>:
>> Except that SSDs will mainly fail due to the amount of write cycles they had
>> to endure.
>>
>> So in RAID-1 your SSDs will fail at almost the same time.
>>
>> With for example 8 OSDs in a server you better spread them out 50/50 over
>> two SSDs.
>
> But the OS should be installed on SSD, to allow the use of the whole
> SATA/SAS disk as OSDs.
> Without RAID-1 between SSDs, a disk failure will result it the whole node down.
> --

True. You might want to use a small internal USB stick like those from 
Transcend for installing your OS. They are available in 4GB and 8GB.

Let syslog handle your logging to an external device and you have almost 
no write I/O on that thing.

This way you can use the SSDs completely for journaling and shrink them 
using HPA with hdparm.

Still, I think that in the distributed nature it shouldn't matter if you 
loose a node. If loosing a node is a to big impact to your cluster, go 
with smaller nodes.

Wido

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