[nflug] Was Partitions sizes, SCSI/IDE bridges/converters

Sun Nov 27 15:57:47 EST 2005

--- Ron Maggio <ronmaggio2005 at yahoo.com> wrote:

> Hi, Dave
>   Sounds like a really nice setup your planning! 
>    
>   "Beware though that if the drives are not in a redundant configuration.
> (i.e. hardware raid 1/5) that adding drives together in a linear fashion will
> increase the likelihood of data-loss as it'll only take one out of the group
> of drives to fail to cause potential data loss". 
>    
>   Yea, this would be a weakness in the system, so one would have to be very
> careful. As you said you do have a second channel available, could you set up
> a dual setup, and mirror the raid might solve the problem? Or would it be
> easier to mirror to another system over the network. Like running dual
> servers, ie: main and backup, but If this is a home based system then it is
> all inane.

Well I could use another IDE channel but I could only run RAID1 in that case
(which is rather space wasteful and provides little performance benefit (for
writes anyways)  If I wanted to go further I'd need to pickup a multichannel
IDE card, and I still wouldn't have TCQ capability (which helps a bit).  By
utilizing the SCSI bus I already have (Dual channel U160), if I want to have
lots of drives and be cheap by not buying native SCSI drives (which are VERY
hard to get in 250GB cpaacities for anything less that 3.5x an IDE drive's
price) I'm going to use the IDE route but use these little know SCSI to IDE
bridges (there are numerous variations out,  some are for CDrom (ATAPI command
set), others are for IDE drives (not sure what exactly is different here) and
the best one is for drives and added TCQ capability.  so for about $150.00 for
a decent IDE drive (I like the samsung spinpoint's as they are completely
silent and they run cool, unlike just about everyone else's drives) plus about
$50.00 for the bridge.  vs about $1200 for a 147GB cheetah U320 drive (U160's
are hard to find now).  Now the 147GB drive is proabbly faster than the
spinpoint,  but for 150 vs 1200.  I can get 8 250GB drives and bridges for the
price of one of the scsi ones. and get higher performance and reliability in a
RAID5 confguration (8 drives in raid 5 = 7*250GB = 1.75TB of usable space,
assuming no hotspares

> The box I have to work with will allow me to run a ATA 133 to serial drive
> raid system, MSI board you see. For now I was only planning to leave in the
> 120gig, but add a DVD -/+ RW Duel layer, and two to three more 120gig or
> larger drives. Or as you state more then two HDD do slow performance, so I
> just could leave in the CD-RW. 
>    
>   I did a bit of figuring with pen and paper to plan out how to allocate
> drive space to each partition, and I ended up with this layout.
>    
>    /boot 100megs, / 10gigs, /usr 25gigs, /usr/local 25gigs, /var 10gigs,
> /home 20gigs, /tmp 10gigs, /opt 10gigs, and /scratch 10gigs. How does that
> sound for starters?
>    

I'd cut /tmp to 1GB, up home to 25GB and up opt to 15GB and leave the rest for
scratch.  NOTE: If you're like me and you encoded your personal CD's to ogg or
mp3 you might want to create a parition to segregate that from the rest of the
system. (I have /media/audio for that)

>   You where talking about SCSI, so that subject I was thinking of how to get
> my IBM Intellistation up and running. I'm looking into SCSI for it, but
> really don't know where to start. I would need a card, have a 68pin cable to
> work with and have room for three drives. I would like to go with 50 to
> 150gig drives if possible, any suggestion? I was planning on using the CD-RW
> on IDE channel 2 as master. 
>   Say any idea if that SCSI to IDE bridge would work with IDE optical drives,
> rather than connecting it through the IDE controller.

Basically I'd recommend an Ultra 160 card, if multichannel even better, as if
you mix single ended (SE) devices (CDrom's and LVD devices (newer HD's or
bridges) the SCSI channel will default to SE mode and slow down to 40MB/sec. 
My controller is a dual U160 and I have  my LVD drives (which are actually
80MB/sec ones) on channel 1 and my other two drives which are Single Ended 
with my CDRW on chanel two.  Hence channel 1 runs at 80MB/sec LVD mode and
channel two runs at 40MB/sec (SE mode). 

The bridges I was looking at are made by ACARD, about $54.00 from newegg.com
http://www.newegg.com/Product/Product.asp?Item=N82E16815114105

The 7726Q is better than the 7726H as the Q series does command queuing and the
H does NOT.  

the 7722 version is ONLY for CD/DVD and/or burners, NOT hard disks. it's about
$58.00
http://www.newegg.com/Product/Product.asp?Item=N82E16815114107

Dave J. Andruczyk

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