On Sat, 24 Oct 1998, Andrew B. Cramer wrote:
> Thanks for responding, the controler works just fine with the Slackware
> installation I have created. The question is what do I do to check the status
> of the array while the server is up and running?
Currently, MegaRAID support isn't too strong, so you can't do what you'd
like to at the moment. After going through the driver sources, I've
noticed hooks which allows implementation of an easy "cat
/proc/scsi/megaraid/1" from the shell to display the status of the array.
However, right now, I'm focusing my attention on getting MegaRAID to work
bug-free with my SMP system. There are problems with spinlocks and the
handling of both the qPending and qCompleted SCB queues. Also, there's a
#define in the code suggesting that the adapter is capable of handling 70
I/O mailboxes, but the driver uses only one of them, which quite likely
explains the poor performance we see under Linux. (For example, I have a
Seagate Hawk that averages 5MB/sec through a BusLogic BT-958. MegaRAIDing
six identical ones together on level 0 drops the transfer rate down to
3MB/sec -- ??? Wasn't RAID 0 suppose to improve transfer speeds?)
I'm also considering writing off the cost of the card entirely and migrate
to software RAID altogether -- it may not be worth the time expense of
mucking through someone else's device driver without any decent hardware
programming docs at all. Despite the claims of some AMI retailers, I'm
skeptical about whether MegaRAID is really better than other RAID adapters
like Mylex or ICP-Vortex (with the best drives money can buy, someone
benched an ICP to over 100MB/sec!). My experience with it has been to the
contrary so far.
-- Kim-Ee
