From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: moving spares into group and checking spares Date: Wed, 14 Sep 2016 23:22:49 +0500 Message-ID: <20160914232249.6e5fc568@natsu> References: <20160914092959.GA3584@metamorpher.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/NMrfV7JCyeINKcngcqFuu9N"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: scar Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/NMrfV7JCyeINKcngcqFuu9N Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 14 Sep 2016 10:52:55 -0700 scar wrote: > i'm not sure what you're suggesting, that 4x 11+1 RAID5 arrays should be= =20 > changed to 1x 46+2 RAID6 array? that doesn't seem as safe to me But you think an 11-member RAID5, let alone four of them joined by LVM is safe? From a resiliency standpoint that setup is like insanity squared. Considering that your expenses for redundancy are 8 disks at the moment, you could go with 3x15-disk RAID6 with 2 shared hotspares, making overall redundancy expense the same 8 disks -- but for a massively safer setup. Also don't plan on having anything survive any of the joined arrays failure (expecting to recover data from an FS which suddenly lost a third of itself should never be part of any plan), and for that reason there is no point in using LVM concatenation, might just as well join them using mdadm RAID0 and at least gain the improved linear performance. --=20 With respect, Roman --Sig_/NMrfV7JCyeINKcngcqFuu9N Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlfZlXwACgkQTLKSvz+PZwijqACfa3XihVrTkNUOLbLpWs34LcRh dG0AnAnhMCjR9dP4I1AhS4cqMDHoRaRa =ptsq -----END PGP SIGNATURE----- --Sig_/NMrfV7JCyeINKcngcqFuu9N--