RE: Mirroring, Striping, Etc.

Vernon Brooks ( merlin@netnevada.net )
Wed, 04 Feb 1998 13:26:47 -0800

Actually, the 2940 can take several drives on it's single channel before
there would be ANY advantage of a 3940. Reason being, the SCSI bus is
something liek 80mb/sec, whereas a single drive can't come close to that.
You only need consider another channel if you can do the math of adding up
the peak of your drives and seeing if it adds up to more than the channel.

At 02:26 AM 2/3/98 -0800, you wrote:
>Mirroring is usually slower unless the SCSI card can do it for you, not the
>case on most Adaptecs. Stripe the set, although you will lose the "mirror"
>type backup of mirroring, but it will increase performance. Also, the 2940
>is a single channel SCSI host, going up to a 3940 and putting each drive on
>separate channels would probably help, but you would need to find out what
>kind of internal bandwidth the hard drives are using on your SCSI
>card...hmmm...I'm not sure how to make this much clearer. :) Going to a
>3940UW would mean upgrading to UltraSCSI 3 WIDE.
>
>----------
>From: Gregory White
>Sent: Monday, February 02, 1998 2:27 PM
>To: ntisp@emerald.iea.com
>Subject: Mirroring, Striping, Etc.
>
>Can someone offer some information regarding performance
>improvements/degradation caused by drive mirroring and striping on NT 4?
>
>We recently added a second drive to our mail server and set it up as a
>mirror drive. Since then, it seems to be slower in responding when sending
>mail. It may just be perception, since I am paying more attention to the
>machine now.
>
>We are running a PP150 w/128 MB Ram and 2- 2.1 GB SCSI on an Adaptec 2940.
>
>
>Thank you,
>
>Greg White
>Direct NET Communications
>
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* Vernon Brooks - merlin@netnevada.net
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