Hi, Seth,
Seth Bardash wrote:
> We build a storage unit that anyone using Centos can build. It is based on
> the 3ware 9750-16 controller. It has 16 x 2 TB Sata 6 gb/s disks. We
> always set it up as a 15 disk RAID 6 array and a hot spare. We have seen
Interesting. We're still playing with sizing the RAID sets and volumes.
The prime consideration for this is that the filesystem utils still have
problems with > 16TB (and they appear to have been saying that fixing this
is a priority for at least a year or two <g>), so we wanted to get close
to that.
This afternoon's discussion has me with 2 17-drive RAID sets and a 6; on
that, one volume set each, which gives us 30TB usable on the two large
RAID sets and 8TB usable on the small one, all RAID 6.
> multiple instances were the A/C has gone off but the customer's UPS kept
> the systems running for an hour or two with no cooling. Once the ambient
> temperature goes above 40C you are stressing all the disks in the array. I
> ramble about this BECAUSE we have seen many RAID 5 arrays fail while
> rebuilding with a hot spare and then loose all the data.
That's not a problem for us - we've got two *huge* units in the server
room, er, computer lab that this RAID box is in.
<snip>
> Also the rebuild time for a 50 TB array is about 12 hours while the array
> is in use and online. But during this time there is little or no
> degradation in performance.
THANK YOU. I'll forward this email to my manager and the other admin -
it's really helpful to know this, even if it isn't your box.
>
> The down side is the cost of the controller. If anyone has questions about
> this I would be glad to answer them off line : at seth at
> integratedsolutions dot org.
>
What came with this are QLogic FC HBAs for the server.
mark