From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Marczykowski Subject: Re: libvirt, libxl and QDISKs Date: Fri, 26 Apr 2013 13:50:18 +0200 Message-ID: <517A69FA.6080402@invisiblethingslab.com> References: <5177EA93.7000403@eu.citrix.com> <1366880153.20256.432.camel@zakaz.uk.xensource.com> <1366889589.20256.510.camel@zakaz.uk.xensource.com> <1366891065.20256.517.camel@zakaz.uk.xensource.com> <51791DB1.9070903@eu.citrix.com> <1366893802.20256.526.camel@zakaz.uk.xensource.com> <51792E1F.3030005@eu.citrix.com> <1366898215.20256.552.camel@zakaz.uk.xensource.com> <5179D7F4.2080408@suse.com> <517A6593.70906@invisiblethingslab.com> <1366976452.3142.73.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5473209418550383957==" Return-path: In-Reply-To: <1366976452.3142.73.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: George Dunlap , Jim Fehlig , xen-devel , Dave Scott , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --===============5473209418550383957== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7E5C30EFC7AC41783DE33561" This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7E5C30EFC7AC41783DE33561 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 26.04.2013 13:40, Ian Campbell wrote: > On Fri, 2013-04-26 at 12:31 +0100, Marek Marczykowski wrote: >> What about old good loop+phy based backend for file disk images? I don= 't want >> whole qemu in dom0 for PV domains, only for handling simple disk backe= nd. >> Additionally sparse images + loop + phy + mount -o discard in domU mak= es the >> images "auto shrinking". Don't know if qemu is able to do this. >=20 > IIRC the problem with loop+phy is that loop doesn't do O_DIRECT and > therefore your data isn't actually on the disk when you might think it > is, which can lead to filesystem corruption even if the f/s is doing > correct barriers. >=20 >> Attached patch, which I currently use for that. If it is close to some= thing >> that would be accepted, I will send it in new thread. >=20 > I think you can use a block script for this (i.e. it does the loop > mount) and avoid patching libxl at all. That's what xend did at least..= =2E This also was solution I've evaluated, but libvirt developers don't want = to hear about disk->script setting in official libvirt, so I still need to p= atch some library. Choosing libxl seems to be more universal. Setting loop in = libxl is also much faster than calling script for that. Perhaps I can rewrite this patch to allow the choice (LIBXL_DISK_BACKEND_= LOOP)? --=20 Best Regards / Pozdrawiam, Marek Marczykowski Invisible Things Lab --------------enig7E5C30EFC7AC41783DE33561 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQEcBAEBAgAGBQJRemn6AAoJENuP0xzK19csev0H/3TZB8QG3kiFE3fbmwtw/Vim 5VHhW4O0t33nlOuPGwoDp/KduZ95zeGI3pKT0Lv4J6IywwnwxzT0vTiLRCzvUC48 kMbh549f2Eib6dcsmkBSLDCDyd4t6UQLCwN/klUA0f9AQloBC53oMh8KiQ/4s7Q6 +GO/Z5Jn1wTgc+vBEAagYGj8BTry0/6KPAwOhGJ6ze13bfnomjC+zeCzkYni2O5C E+Aqq145rEP8Xuhsvf47sYVQNb9lGqOtI6skK+G/Uu4rCVu4n9mDBe+I7tatGf74 OtZ/YveqiAzTxGEc/F6VPBHfL41lE/nf4xbHVQQhOGAZ5qe3+TZB2TQy/CXUA/4= =K0Tu -----END PGP SIGNATURE----- --------------enig7E5C30EFC7AC41783DE33561-- --===============5473209418550383957== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============5473209418550383957==--