bcops
asked on
SCSI RAID Question - How many channels?
Hello all,
I've been googling for this all afternoon, but to no avail, so I thought I'd turn to you good folk for the answer (hopefully).
Basically, I want to know....
How many channels are required to do SCSI RAID mirroring of two SCSI drives?
On the market there are cards with up to four channels on them (possibly more), but there are also RAID cards with a single channel on them.
I understand that IDE and SCSI are different, and that for IDE RAID you need at least two channels, and I also understand that SCSI runs parallel information, and hence can have multiple devices attached to a single channel, but i need a concrete answer before I spend our hard earned budget on a SCSI RAID card
Thank you in advance
Ben
I've been googling for this all afternoon, but to no avail, so I thought I'd turn to you good folk for the answer (hopefully).
Basically, I want to know....
How many channels are required to do SCSI RAID mirroring of two SCSI drives?
On the market there are cards with up to four channels on them (possibly more), but there are also RAID cards with a single channel on them.
I understand that IDE and SCSI are different, and that for IDE RAID you need at least two channels, and I also understand that SCSI runs parallel information, and hence can have multiple devices attached to a single channel, but i need a concrete answer before I spend our hard earned budget on a SCSI RAID card
Thank you in advance
Ben
Hi bcops,
> How many channels are required to do SCSI RAID mirroring of two SCSI drives?
One channel is enough, it depends on the kind of SCSI card you're using if you can attach 7 or 15 devices on one cable.
But for safety (and gain of speed) I suggest you to take one channel for each part of a mirror.
Greetings,
LucF
> How many channels are required to do SCSI RAID mirroring of two SCSI drives?
One channel is enough, it depends on the kind of SCSI card you're using if you can attach 7 or 15 devices on one cable.
But for safety (and gain of speed) I suggest you to take one channel for each part of a mirror.
Greetings,
LucF
Depeneds on the level of data protection and down time you want.
The generally accepted way is to use two controllers or at least a dual channel controller.
With a single controller if there is a problem with the controller it could cause a problem with both drives.
The generally accepted way is to use two controllers or at least a dual channel controller.
With a single controller if there is a problem with the controller it could cause a problem with both drives.
>>With a single controller if there is a problem with the controller it could cause a problem with both drives.<<
Which is why you don't want to sell yourself short on a quality RAID card.
We only use singles in all 96 of our servers and have never found a need for dual-controllers...
Just fyi from my experience.
Which is why you don't want to sell yourself short on a quality RAID card.
We only use singles in all 96 of our servers and have never found a need for dual-controllers...
Just fyi from my experience.
ASKER
Thank you all so far
~~sirbounty~~
Do you use two single channel cards in your machines to achieve RAID functionality? We aren't bothered about striping, only mirroring. (and in answer to your earlier question, both drives will be mounted internally).
Could you recommend a brand or model for us to use? (we're uk based, so something available worldwide would be useful)
Thank you again (points on their way)
Ben
~~sirbounty~~
Do you use two single channel cards in your machines to achieve RAID functionality? We aren't bothered about striping, only mirroring. (and in answer to your earlier question, both drives will be mounted internally).
Could you recommend a brand or model for us to use? (we're uk based, so something available worldwide would be useful)
Thank you again (points on their way)
Ben
ASKER
And in addition to the previous comment,
If we went with two single SCSI cards, do they need to be RAID cards (instead of simple SCSI controllers) to achieve RAID Mirroring?
If we went with two single channel SCSI RAID cards, how would you configure the system, so that the two RAID bios' on the cards did not conflict?
Cheers again
Ben
If we went with two single SCSI cards, do they need to be RAID cards (instead of simple SCSI controllers) to achieve RAID Mirroring?
If we went with two single channel SCSI RAID cards, how would you configure the system, so that the two RAID bios' on the cards did not conflict?
Cheers again
Ben
ASKER CERTIFIED SOLUTION
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You can set up your RAID array on a single channel.
Limitation is that if you're going to use an external combined with an internal drive array, you'd need two channels...
Doesn't sound like your scenario tho - what's your hardware?
~sirbounty