Subject: Re[4]: differential scsi controllers
To: None <current-users@NetBSD.ORG, mouse@Rodents.Montreal.QC.CA>
From: None <>
List: current-users
Date: 07/02/1998 13:40:07
     i think of it this way=2E  lets say i have two 1 gig disks=2E  one opt=
     is to use ccd to create a single 2 gig striped volume=2E  the other=20
     option is to use them as two seperate 1 gig disks=2E
     either way my effective storage is 2 gigs=2E  the advantage on the ccd=
     side is speed and possibly storing structures that are too large to=20
     fit on a 1 gig disk=2E
     in the non-ccd scenario if one disk goes bad i lose half of the data i=
     was storing (the data that was on the disk that went bad)=2E =20
     in the ccd scenario if one disk goes bad then i lose all of the data=20
     that was stored on both the drive that went bad and the drive that=20
     still works (lost as in it is now in an usable form)=2E
     whether the ccd scenario is fragile or not depends on your=20
     perspective=2E  compared to the non ccd scenario i would say that it i=
     for me, i dont really have a need to use raid0 or raid1=2E  but if=20
     someday i get 5 disks all of the same type i would find raid5 very=20

______________________________ Reply Separator ____________________________=
Subject: Re: Re[2]: differential scsi controllers
Author:  MIME:mouse@Rodents=2EMontreal=2EQC=2ECA at INTERNETALFALAVAL
Date:    1998-07-02 13:24

>>> Our policy is to simply say "ccd is useful only for building large,=20
>>> fast, striped volumes which are also fragile as hell" and recommend=20
>> define "fragile as hell"?  [=2E=2E=2E], I've _never_ had a problem with
>> any of my ccd's except in the case where one of the disks failed=2E
>> Since recovery from hardware failure isn't in the current=20
>> feature-set, I don't call that a fault=2E
>> Missing features does not equate to fragile=2E
> if one disk dies in a striped volume (a volume without parity) all is=20
> lost=2E  i would call that fragile=2E
I wouldn't, no more fragile than any other filesystem on a NetBSD=20
machine=2E  Lose a disk, lose what's on it; ccds make this worse only in=20
that they (potentially) make a filesystem depend on more than one disk=2E
In short, I agree with the double-quoted text above=2E
der Mouse
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