From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: RAID6 and crashes (reporting back re. --bitmap) Date: Mon, 14 Jun 2010 15:14:25 +0600 Message-ID: <20100614151425.11f91562@natsu> References: <4C1128C2.4020105@meetinghouse.net> <001501cb091f$07ac4e40$1704eac0$@woodlea.com> <20100611145019.6f1a5e7d@notabene.brown> <201006131628.35037.bernd.schubert@fastmail.fm> <20100614090520.2ae5a961@notabene.brown> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/J/Dp9Vw4KHJ4DF/hq6Ea09p"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20100614090520.2ae5a961@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Bernd Schubert , linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/J/Dp9Vw4KHJ4DF/hq6Ea09p Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Mon, 14 Jun 2010 09:05:20 +1000 Neil Brown wrote: > > While I have done this myself a couple of times, I still do not underst= and=20 > > where it takes the disk space for the bitmap journal from? Is this space > > mdadm reserved for this purpose? >=20 > Sort-of. > It uses space that the alignment requirements of the metadata assure us is > otherwise unused. > For v0.90, that is limited to 60K. For 1.x it is 3K. I have now: md0 : active raid5 sdf3[3] sde3[1] sda3[0] 3887004672 blocks super 1.2 level 5, 64k chunk, algorithm 2 [3/3] [UU= U] bitmap: 1/8 pages [4KB], 131072KB chunk Metadata is 1.2, and the internal bitmap is 8 pages, which is 32K, not 3K. Did I misunderstand something, or perhaps 3K was a typo? --=20 With respect, Roman --Sig_/J/Dp9Vw4KHJ4DF/hq6Ea09p Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAkwV8vEACgkQTLKSvz+PZwhqyACfRXKK1AYUNOYr/P12eonsiGvZ oDoAn2HOfK/z8xoQ9ALzLUujZ0LGr8CK =CVEF -----END PGP SIGNATURE----- --Sig_/J/Dp9Vw4KHJ4DF/hq6Ea09p--