Subject: Re: on ccd and large disk array
To: Alexander B. Povolotsky <>
From: Curt Sampson <>
List: netbsd-users
Date: 10/21/1997 16:40:27
On Tue, 21 Oct 1997, Alexander B. Povolotsky wrote:

> We're making a (relatively) large disk array using ccd: 5 Micropolis HDDs, 
> 8.7 Gb each, i.e. about 40 Gb total.
> Does anyone know possible traps on our way? Is FFS as-is stable on 40 Gb 
> filesystems? What may we need to patch?

I can't see any reason why a little one like that would be a problem. :-)

If you wanted to do a slightly larger one, you might follow the
lead of NASA Ames Research Laboratory. Take a couple of racks of
9 x 9 GB drives and put a hardware RAID-5 across them, for about
150 GB of storage:

sd9: 156260MB, 12594 cyl, 64 head, 141 sec, 512 bytes/sect x 320020992 sectors

Then take 4 of those and put a ccd across it, and put FFS on that:

Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
/dev/ccd0a  637453560        8 605580872     0%    /mnt

That gives you a little over 600 GB on a single FFS. Of course,
that's probably not enough storage, so you want to have a couple
of those to bring it over a terrabite.

This is NetBSD running on a smallish AlphaServer 8400 (only 2 GB
RAM, 72 PCI slots [on 19 buses], one or two 800 MB HPPI buses).
There's four more with similar amounts of storage kicking around
the lab, too.

(If you FreeBSD guys ever feel like upgrading that little FTP
server of yours you have over at Walnut Creek, feel free to give
us a call. :-))


Curt Sampson	   Info at
Internet Portal Services, Inc.	   Through infinite myst, software reverberates
Vancouver, BC  (604) 257-9400	   In code possess'd of invisible folly.