Date: Sun, 18 Jun 2006 22:44:36 -0400 (EDT) From: Ensel Sharon <user@dhp.com> To: Eric Anderson <anderson@centtech.com> Cc: freebsd-fs@freebsd.org, freebsd-questions@freebsd.org Subject: Re: Please help - adaptec 2820sa not ... RESOLVED Message-ID: <Pine.LNX.4.21.0606182241540.12027-100000@shell.dhp.com> In-Reply-To: <449606B8.5080106@centtech.com>
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On Sun, 18 Jun 2006, Eric Anderson wrote: > > 6.1 sysinstall does in fact see both 2820sa controllers, and when I put in > > a single 160GB sata drive, it does see that single drive and I can install > > onto it, etc. > > > > Sysinstall does _not_ see my 2.7TB raid6 array. I suspect that if it were > > smaller than 2TB, it would see it correctly. > > > > I have a number of options with which to deal with this, all of which > > involve either wasting money or wasting disk space. Fantastic. > > Right - FreeBSD doesn't recognize >2TB LUNs. You should make two LUNs, > and concat them or stripe them with GEOM. Don't use the large partition > for the OS either. > > You shouldn't waste either disk space or money. Let's say I have 8 disks. Let's say I require raid6. If I make one array, I lose 25% to raid overhead. If I make two arrays, I lose 50% to raid overhead. So it would seem that my inability to use a >2TB LUN does indeed lose me both space and waste money. My solution is to use two disks as a mirror, and use the other six for a raid6 array, thus losing 3/8 to raid overhead instead of 4/8, but it's still worse than 2/8 which is what I wanted to do ... Perhaps I misunderstand you ?
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