From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from frost.carfax.org.uk ([85.119.82.111]:59160 "EHLO frost.carfax.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387502AbeHAKkp (ORCPT ); Wed, 1 Aug 2018 06:40:45 -0400 Date: Wed, 1 Aug 2018 08:56:02 +0000 From: Hugo Mills To: MegaBrutal Cc: linux-btrfs Subject: Re: BTRFS and databases Message-ID: <20180801085602.GC7524@carfax.org.uk> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HG+GLK89HZ1zG0kk" In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: --HG+GLK89HZ1zG0kk Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 01, 2018 at 05:45:15AM +0200, MegaBrutal wrote: > I know it's a decade-old question, but I'd like to hear your thoughts > of today. By now, I became a heavy BTRFS user. Almost everywhere I use > BTRFS, except in situations when it is obvious there is no benefit > (e.g. /var/log, /boot). At home, all my desktop, laptop and server > computers are mainly running on BTRFS with only a few file systems on > ext4. I even installed BTRFS in corporate productive systems (in those > cases, the systems were mainly on ext4; but there were some specific > file systems those exploited BTRFS features). >=20 > But there is still one question that I can't get over: if you store a > database (e.g. MySQL), would you prefer having a BTRFS volume mounted > with nodatacow, or would you just simply use ext4? Personally, I'd start with btrfs with autodefrag. It has some degree of I/O overhead, but if the database isn't performance-critical and already near the limits of the hardware, it's unlikely to make much difference. Autodefrag should keep the fragmentation down to a minimum. Hugo. > I know that with nodatacow, I take away most of the benefits of BTRFS > (those are actually hurting database performance =E2=80=93 the exact CoW > nature that is elsewhere a blessing, with databases it's a drawback). > But are there any advantages of still sticking to BTRFS for a database > albeit CoW is disabled, or should I just return to the old and > reliable ext4 for those applications? >=20 >=20 > Kind regards, > MegaBrutal --=20 Hugo Mills | In theory, theory and practice are the same. In hugo@... carfax.org.uk | practice, they're different. http://carfax.org.uk/ | PGP: E2AB1DE4 | --HG+GLK89HZ1zG0kk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJbYXWiAAoJEFheFHXiqx3kc2MP/0NrsYr48BifmgTOlJNvtZPH jUH1DOnk+uGdUdkbC3Svi2oLyqJOMCgXDpRW4Ntjr7udXq+pHcNBUG9IEYm8v8Bl Fz0DjIFOCV44HVPyiBr8nmwnxrHF7z1ApTlq9nv6/TqeRHeOpsiq9IUP4Ay3NKFX ZKGn+xbj4vF45uC9xtZ494CAlTohn+X11iPilmJ7sqgXKEIzn3LHI4UDSatHHQCM 2aJ/O5HUgLrouBt0zVCXJ8o5IlgThZO9DNw7pFW817AntbZ/hZu7SwiZXBH9w3e1 Pz3bLskLMF1Be/dOLlKuzzxlSeyaQmv2p2wp6rOabQ1i/7ozEzqLUpQohrBzx0oW 3hUizz7yncVsBmFXiY8bz2EXGvUv2+YSF5WYjfkUIsrumo8xRt8gcqpXkOV8HtnC wKd4P6AJGGf3XJ1fWGNcBKM3LhKdYgBpU+z8txS9njZiLnnEFO3HQOgiaku+WfeP EXhFvWcu/YaFzYi1BS2ULGwuBpoyR/E+o9nsWyDpGNZoB1Uounx6eAIZwbDfW7ip PnLcsWt8SB0QW5N6UiIa2TxhnXFPqYFQL3O/PhdfDKd24mEF/c3XGi4uZdtvXhP9 RXPobdwEMO/qoqo5keW+MUbUnwyZ9mCuv6v6a4r6inj0azF7CBZjofAgsKA+t2tI vP8Yfq3I4zaRYVB0TZ+s =ufgD -----END PGP SIGNATURE----- --HG+GLK89HZ1zG0kk--