From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp65.ord1c.emailsrvr.com ([108.166.43.65]:35116 "EHLO smtp65.ord1c.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752893AbbFQN3W (ORCPT ); Wed, 17 Jun 2015 09:29:22 -0400 Received: from smtp9.relay.ord1c.emailsrvr.com (localhost.localdomain [127.0.0.1]) by smtp9.relay.ord1c.emailsrvr.com (SMTP Server) with ESMTP id 9C5B1380408 for ; Wed, 17 Jun 2015 09:29:21 -0400 (EDT) Received: from smtp9.relay.ord1c.emailsrvr.com (localhost.localdomain [127.0.0.1]) by smtp9.relay.ord1c.emailsrvr.com (SMTP Server) with ESMTP id 7C59C3803F6 for ; Wed, 17 Jun 2015 09:29:21 -0400 (EDT) Received: by smtp9.relay.ord1c.emailsrvr.com (Authenticated sender: vincent-AT-up4.tv) with ESMTPSA id 48359380130 for ; Wed, 17 Jun 2015 09:29:16 -0400 (EDT) Content-Type: multipart/signed; boundary="Apple-Mail=_1E051B75-4CAE-4FBA-BA8C-5AF101B0FD0A"; protocol="application/pgp-signature"; micalg=pgp-sha512 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: RAID10 Balancing Request for Comments and Advices From: Vincent Olivier In-Reply-To: <20150617132736.GT9850@carfax.org.uk> Date: Wed, 17 Jun 2015 09:29:06 -0400 Message-Id: <48569892-8E0C-4C28-87B1-60CD562AA9EF@up4.com> References: <1434456557.89597618@apps.rackspace.com> <20150616122545.GI9850@carfax.org.uk> <61CBE6C4-0D06-4F16-B522-4DBB756FBC31@up4.com> <80BA2964-3B67-430B-99BE-62A348C5DBED@up4.com> <20150617132736.GT9850@carfax.org.uk> To: linux-btrfs@vger.kernel.org Sender: linux-btrfs-owner@vger.kernel.org List-ID: --Apple-Mail=_1E051B75-4CAE-4FBA-BA8C-5AF101B0FD0A Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Jun 17, 2015, at 9:27 AM, Hugo Mills wrote: >=20 > On Wed, Jun 17, 2015 at 09:13:08AM -0400, Vincent Olivier wrote: >>=20 >>> On Jun 16, 2015, at 8:14 PM, Chris Murphy = wrote: >>>=20 >>> On Tue, Jun 16, 2015 at 5:58 PM, Duncan <1i5t5.duncan@cox.net> = wrote: >>>=20 >>>> On a current kernel unlike older ones, btrfs actually automates = entirely >>>> empty chunk reclaim, so this problem doesn't occur anything close = to near >>>> as often as it used to. However, it's still possible to have = mostly but >>>> not entirely empty chunks that btrfs won't automatically reclaim. = A >>>> balance can be used to rewrite and combine these mostly empty = chunks, >>>> reclaiming the space saved. This is what Hugo was recommending. >>>=20 >>> Yes, as little as a -dusage=3D5 (data chunks that are 5% or less = full) >>> can clear the problem and is very fast, seconds. Possibly a bit >>> longer, many seconds o single digit minutes is -dusage=3D15. I = haven't >>> done a full balance in forever. >>=20 >>=20 >> Yes, on this 80% full 6x4TB RAID10 -dusage=3D15 took 2 seconds and = relocated "0 out of 3026 chunks=E2=80=9D. >>=20 >> Out of curiosity, I had to use -dusage=3D90 to have it relocate only = 1 chunk and it took les than 30 seconds. >>=20 >> So I put a -dusage=3D25 in the weekly cron just before the scrub. >=20 > In most cases, all you need to do is clean up one data chunk to > give the metadata enough space to work in. Instead of manually > iterating through several values of usage=3D until you get a useful > response, you can use limit=3D to stop after successful block > group relocations. Nice! Will do that instead! Thanks. --Apple-Mail=_1E051B75-4CAE-4FBA-BA8C-5AF101B0FD0A Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJVgXYiAAoJEOggPckf4s14TXwP+wW9qUHkbG8l3UvsHWIokEMA PFXxCJOeyj3ayw8Fe6Ro0u87VY0r8VMl9mpcEZA0gvvN4H9BesM0AKp0H7L2gwpJ 1dH8egLvKnGHU+/Nxujqfk9X2+eB+swHRtzNzytaR07B45QIuuAe2PpX9eY1Jzhd Y6CMvAiq2AncU6EXBTyvdU78Xt9qdoxQ3NuevL+c0lNNYNGUmFUkIQ8E/PY3+CqG DhV8pDnxXVoPlZRuxRQ0CxPXxqk9nabwdUdUmjLsQGZksIzCxFtmRDHOvEO81qBh K4oY6RejufwchNsAskRm8xdMhq1K7aDARUmeWeNnaHowvFe6UcGQqdFqikehLPip vWu5QkEa4kG9I8Idm7cQZTRAB0FaZXElvv8wwiJJn1vkjRZXnPV2xMLQrkSs/WRJ xtfIhn5u4Dot61IZGE1QjyRMTvB7rKyEjqDfcFHr7/ZOK9y5a+gAVOX0I5gxHbWD YK9ouFIlwKsY5mPZwrvmhtTIvWxgjvXuWeje+iecUnoTHWXo8vPVVQr81S6hYwb5 pmzATXpNYr1hk2mTphsv273Si/7fodol8IviKBv4AJuTSWffZeyu/Ef1GWJgzEoa x4bdlr+MG6R1nOLAxyco/KD0NMMX9ywGIAConDrsdAnw6Z0BA2/rbYgiv+oC8GMS zc0/Vobju6eDPMa0oJ8a =17sm -----END PGP SIGNATURE----- --Apple-Mail=_1E051B75-4CAE-4FBA-BA8C-5AF101B0FD0A--