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Best way to connect RAID Card channels for RAID 10?

Hi All,

We have a server that we are now ready to configure so as to serve our companies main databases to our staff situated across the country!

The question however!?

We would like to use RAID 10 for the database mount point in linux (RHEL 5).  We have a nice Intel SRCU42X (PCI-Express) card serving 2 SCSI HDD backplanes (namely a 6 bay and 4 bay = ten disks) connected in the Intel SC5300BD2 server.

In your experiences, what is the best way to configure the ARRAYS and LOGICAL DRIVE in the Intel Raid Controller BIOS program?  ie...I would like to have the RAID 10 volume configured in such a way so as to have the striping running between the 2 hard disk channels (the 2 HDD bays) and have the mirroring of each respective striped drive stay on that respective hard drive bay/channel?
Will this bring about max disk io performance??

Any suggestions would be much appreciated as we're ready to kick off with proceedings!!

A data block "abcd"
SCSI Channels	
I	II	- Option 1 - STRIPES across the 2 scsi channels/hdd backplane
a	b
c	d
a	b
c	d
a	a           - Option 2 - MIRRORS running across the 2 scsi channels/hddbackplane
b	b
c	c
d	d

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2 Solutions
bexcoAuthor Commented:
Also, further information...
The Intel RAID BIOS Configuration Software wants you to define arrays.  Once you've defined your arrays should you want to configure raid10 you need to select minimum 2 arrays and enable "SPANNING".  This then creates the RAID 10 "LOGICAL DRIVE".  Do we compile these arrays from a selection/spread of disks across the 2 channels or should we use only disks connected to the same channel?

Array1 = CHANNEL 0 DISK 1 + CHANNEL 1 DISK 1 (different disks from different channels)
Array1 = CHANNEL 0 DISK 1 + CHANNEL 0 DISK 2 (all disks coming from the same channel)

To build the RAID 10 config on this card, one has to select multiple ARRAYS and then from the LOGICAL DRIVE screen define it as a RAID 1 VOLUME WITH "SPANNING".  
From that, Does that mean that the ARRAYS will be mirrored?  Does that mean that when you define the drives that make up the array, those drives would ultimately be the "striped" component of the RAID 10 volume?

Sorry for the lengthy text...I'm typing out aloud!  Has anyone any confirmed experience as to Intel and the way in which their cards "span" and build raid 10 volumes?

Best way is to have a on one channel, a' on the other, then you can lose a complete channel and keep going. But it's not that configurable, and since it supports drive roaming you could power off, swap a couple of disks around, power on and the mirrors on seperate channels best practice would be broken.
Andy is right, but let me add that if you split disks across channels then it won't buy you better performance, at least not with just 2 disks.  You won't get close to saturating the channel.
bexcoAuthor Commented:
A number of months later and our server configuration is running nicely with some good performance on the disks.  Thanks to the experts for their comments, dlethe interesting your comment on the inability to saturate the channel with say 2 disks.  I wonder whether the channel would be saturated with 6 disks connected to it??

I will [finally] award the points to both of you!

Thanks and Regards
bexcoAuthor Commented:
Question was about performance benefits.  Limitations in the Intel configuration software, limited benchmark performance availability and the answer becomes one of educated opinion.
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