We currently have a FAS940C cluster. Each of the FAS940 has 2 DS14 shelves of 36 GB drives and 1 DS14 shelf of 72 GB drives (a total of 6 shelves). Each of the FAS940 has only 1 FC dual-channel Host Adapter:
slot 4: FC Host Adapter 4a (Dual-channel, QLogic 2312 rev. 2, 64-bit, L-port, <UP>)
We are trying to isolate some performance problem we are encourtering. How do we find out if the host adapter is the bottleneck? Does anyone have a formula for calculating how many drives can be put on a single loop without losing performance. Thanks.
Derek
supported (see config guide on NOW): are 4 ds14 shelves (with lrc) on 1 loop. are 6 ds14 shelves (with esh) on 1 loop.
imho performance will increase if you add 1 fc-hba to each node and dual attach the shelves with esh-modules.
Derek Lai wrote:
We currently have a FAS940C cluster. Each of the FAS940 has 2 DS14 shelves of 36 GB drives and 1 DS14 shelf of 72 GB drives (a total of 6 shelves). Each of the FAS940 has only 1 FC dual-channel Host Adapter:
slot 4: FC Host Adapter 4a (Dual-channel, QLogic 2312 rev. 2,64-bit, L-port, <UP>)
We are trying to isolate some performance problem we are encourtering. How do we find out if the host adapter is the bottleneck? Does anyone have a formula for calculating how many drives can be put on a single loop without losing performance. Thanks.
Derek
Hi toasters,
Hannes Herret - Bacher Systems EDV GmbH wrote:
supported (see config guide on NOW): are 4 ds14 shelves (with lrc) on 1 loop. are 6 ds14 shelves (with esh) on 1 loop.
Thats right.
Talking about performance with more FC busses:
Your average FC-Drive will give your somewhere around 40-50 MB/s troughput, so your bus with 1 GBit will probably be maxed out at 3 drives already, with the mk2-shelves (2GBit) double that number. So more than the recommended number of shelves will NOT give you any better performance.
If you really want to max things out get the mk2-shelf and run a multipathing setup. Remember, clustering is not possible with the mutlipath setup, since the cluster-partner connects via the B-Port of the disk-shelf.
- Olli
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Derek Lai -
Hannes Herret - Bacher Systems EDV GmbH -
Oliver Kuegow