From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: clustered MD - beyond RAID1 Date: Tue, 22 Dec 2015 07:47:12 +1100 Message-ID: <87bn9j4jhr.fsf@notabene.neil.brown.name> References: <56742652.5040304@nasa.gov> <87si2w66tm.fsf@notabene.neil.brown.name> <567850C4.30108@bnl.gov> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: <567850C4.30108@bnl.gov> Sender: linux-raid-owner@vger.kernel.org To: Tejas Rao , Scott Sinno , linux-raid@vger.kernel.org Cc: "Knister, Aaron S. (GSFC-606.2)[COMPUTER SCIENCE CORP]" List-Id: linux-raid.ids --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, Dec 22 2015, Tejas Rao wrote: > What if the application is doing the locking and making sure that only 1= =20 > node writes to a md device at a time? Will this work? How are rebuilds=20 > handled? This would be helpful with distributed filesystems like=20 > GPFS/lustre etc. > You would also need to make sure that the filesystem only wrote from a single node at a time (or access the block device directly). I doubt GPFS/lustre make any promise like that, but I'm happy to be educated. rebuilds are handled by using a cluster-wide lock to block all writes to a range of addresses while those stripes are repaired. NeilBrown --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJWeGVQAAoJEDnsnt1WYoG5uMAP/3JHF3UyXgF3d/bAcLgY8/IF gQLZtZNi2GqP3gPG9YyNZduuR8z5zXTO9qWK4VaUcIFeboaAku/V6A/cvoylugK/ RJjk5is/K8jpM6EaSGs24zaqoGULcBM/+pyFAYhjvQzIoeF1RBOK7zEZV9QmmjkN ddZVKCbDVmUwEEhEqn6b+aG07zMsPzK5WD0onT+vDHd0RFrQxcpxE+JOghPMab9B ctIqZhgIdLfEgp8wzHejccquVNbhTGQNpv87yjrg8JPKgiTVegUqfGBJWtIwoFMQ v4OQv9EwsuS165urGgeDDfhpLsNKDqBAUCLrY7IdDMFV5hbg3CPVofd03yovIOA7 jFz0nQJNYwV/IdTyjYhUcMIsNjajZtP8jqCbBttgYI/VEvrwJi6+RuXf+5Wn5B5m fpkxLvMjncW8rTgCuhhR+SCZ6whlDqc9kRP5Ci3uD98OEAzEnXRoEzrI4kh0KPF4 /WBm2MSs1Z2YLnIP0ZxgnQi9O3bw3oRqIhETyACnGTzB5r4UGLDloWZ4ITRTm5JD d0fqyOrbjKKlzBWxEm0LDCX6shNIc6zFrHN+3tpo4tptoNcnfbSc9Zyiw467ElpF ZDlstsRGHLDzv3nSAburU1VA/4T+8X7eBVCJ6+SkxGDLmQydI49FV5fLb0eNb52C nh0Ygwysi47ZufNBcFzy =hnt8 -----END PGP SIGNATURE----- --=-=-=--