On Fri, 18 Feb 2011, Stan Hoeppner wrote:
Mattias Wadenstein put forth on 2/18/2011 7:49 AM:
Here you would either maintain a large list of nfs mounts for the read
load, or start looking at a distributed filesystem. Sticking them all
into one big fileserver is easier on the administration part, but
quickly gets really expensive when you look to put multiple 10GE
interfaces on it.
This really depends on one's definition of "really expensive". Taking
the total cost of such a system/infrastructure into account, these two
Intel dual port 10 GbE NICs seem rather cheap at $650-$750 USD:
http://www.newegg.com/Product/Product.aspx?Item=N82E16833106037
http://www.newegg.com/Product/Product.aspx?Item=N82E16833106075
20 Gb/s (40 both ways) raw/peak throughput at this price seems like a
bargain to me (plus the switch module cost obviously, if required,
usually not for RJ-45 or CX4, thus my motivation for mentioning these).
The storage infrastructure on the back end required to keep these pipes
full will be the "really expensive" piece.
Exactly my point, a storage server that can sustain 20-200MB/s is rather
cheap, but one that can sustain 2GB/s is really expensive. Possibly to the
point where 10-100 smaller file servers are much cheaper. The worst case
here is very small random reads, and then you're screwed cost-wise
whatever you choose, if you want to get the 2GB/s number.
[snip]
RAID 5/6 need not apply due the abysmal RMW partial stripe write
penalty, unless of course you're doing almost no writes. But in that
case, how did the data get there in the first place? :)
Actually, that's probably the common case for data analysis load. Lots of
random reads, but only occasional sequential writes when you add a new
file/fileset. So raid 5/6 performance-wise works out pretty much as a
stripe of n-[12] disks.
/Mattias Wadenstein
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
