From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailgw-02.dd24.net ([193.46.215.43]:55614 "EHLO mailgw-02.dd24.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750798AbbLLWPn (ORCPT ); Sat, 12 Dec 2015 17:15:43 -0500 Message-ID: <1449958538.15961.3.camel@scientia.net> Subject: Re: btrfs: poor performance on deleting many large files From: Christoph Anton Mitterer To: Duncan <1i5t5.duncan@cox.net>, linux-btrfs@vger.kernel.org Date: Sat, 12 Dec 2015 23:15:38 +0100 In-Reply-To: References: <1448488198.4717.4.camel@gmail.com> <1448562347.8809.16.camel@scientia.net> <1448582805.11377.9.camel@scientia.net> <1448683025.6837.4.camel@scientia.net> Content-Type: multipart/signed; micalg="sha-512"; protocol="application/x-pkcs7-signature"; boundary="=-vhErYdQMAdg/N3Kcj3VD" Mime-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: --=-vhErYdQMAdg/N3Kcj3VD Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2015-11-28 at 06:49 +0000, Duncan wrote: > Christoph Anton Mitterer posted on Sat, 28 Nov 2015 04:57:05 +0100 as > excerpted: > > Still, specifically for snapshots that's a bit unhandy, as one > > typically > > doesn't mount each of them... one rather mount e.g. the top level > > subvol > > and has a subdir snapshots there... > > So perhaps the idea of having snapshots that are per se noatime is > > still > > not too bad. > Read-only snapshots? So you basically mean that ro snapshots won't have their atime updated even without noatime? Well I guess that was anyway the recent behaviour of Linux filesystems, and only very old UNIX systems updated the atime even when the fs was set ro. > That'd do it, and of course you can toggle the read- > only property (see btrfs property and its btrfs-property manpage). Sure, but then it would still be nice for rw snapshots. I guess what I probably actually want is the ability to set noatime as a property. I'll add that in a "feature request" on the project ideas wiki. > Alternatively, mount the toplevel subvol read-only or noatime on one=20 > mountpoint, and bind-mount it read-write or whatever other > appropriate=20 Well it's of course somehow possible... but that seems a bit ugly to me... the best IMHO, would really be if one could set a property on snapshots that marks them noatime. Cheers, Chris. --=-vhErYdQMAdg/N3Kcj3VD Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCCEZIw ggW/MIIDp6ADAgECAgMCOakwDQYJKoZIhvcNAQENBQAwVDEUMBIGA1UEChMLQ0FjZXJ0IEluYy4x HjAcBgNVBAsTFWh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzEcMBoGA1UEAxMTQ0FjZXJ0IENsYXNzIDMg Um9vdDAeFw0xNDA2MTIxNjM2MThaFw0xNjA2MTExNjM2MThaMHwxITAfBgNVBAMTGENocmlzdG9w aCBBbnRvbiBNaXR0ZXJlcjEkMCIGCSqGSIb3DQEJARYVY2FsZXN0eW9Ac2NpZW50aWEubmV0MTEw LwYJKoZIhvcNAQkBFiJtYWlsQGNocmlzdG9waC5hbnRvbi5taXR0ZXJlci5uYW1lMIIBIjANBgkq hkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA4phP/j9vT9dZT+k3ffHxvRWMOuzBnu5O3Fl4y2+WL7pL rfLiEhWzGXhHvjSqpt4vCNSdqy43453nnu8+hMb+uEtqSIL1AHU5eLhuDNVN9S4bt9E7nA2WKYBU LCUi/xCD/GL7ToyJNwhrhzcCZ7pXSc3xVqFoC4f6weU9ExhoEZQNRpTM0BFCOi4fRxvKFNnUYgjK hqy0Ta5H0Xx86mAp0Q4dxoD7mhI5iTF6TRkUheELxF24JCuAf04M89Cwft6DRH1FpJ3yvgW2B5U5 aFSL4ZnF4N/wyCB7Dkm1rQ7RCAvw5btkf0VdPnU7ccDCx8HEc2nxK/lbCjrznvh3sa1CCwIDAQAB o4IBcDCCAWwwDAYDVR0TAQH/BAIwADBWBglghkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNl cnRpZmljYXRlIGZvciBGUkVFIGhlYWQgb3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYD VR0PAQH/BAQDAgOoMEAGA1UdJQQ5MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYK KwYBBAGCNwoDAwYJYIZIAYb4QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDov L29jc3AuY2FjZXJ0Lm9yZzA4BgNVHR8EMTAvMC2gK6AphidodHRwOi8vY3JsLmNhY2VydC5vcmcv Y2xhc3MzLXJldm9rZS5jcmwwRAYDVR0RBD0wO4EVY2FsZXN0eW9Ac2NpZW50aWEubmV0gSJtYWls QGNocmlzdG9waC5hbnRvbi5taXR0ZXJlci5uYW1lMA0GCSqGSIb3DQEBDQUAA4ICAQBefctiLgGl e5baspuozyA4k7Up7SVhGHbif6pQfoFc/9Thx9GXnYpX+U64PMyWBfWwHZIy52Vg0RVkvPi1t6mi GyBfoSpC6ooR0bKWtUIogw/ymqKWlTLVR8kbLqRmRk4juMtCXG2K3yMygX/rjkuUSuFj2Bjpkmzg CtMojbUMYbszePmhQ7DJ62YEdtKpcjN94QAsI5GWlIAbs3KJazAcaNCRJeXCLcUMchyKHJA+NXH5 az/ekBxBMBzJP2An20PP88UI4JW18z31KiG9UVGa2uO4l4aWgVe2GnhNEdCD/o48msJEWKAt5vl2 yMqr7ihmNPocU2+/FW0xPe/vftdOTD9pgXdSGf4prdD+23q2YvpalOCzr2p8yCJZNVBPMxAP4mL0 3OEktXza4wohqAmceXKfGUNwRGBaPvtIGnPrpLhCQ+2YJDg8g1UEsk23bKyZlJWeKJyVqOBsDJmj aBsN/qKhQFnav+zQdqGhMeaSisF/53mD3gyVYg2JRl18apgGbg32kyLmomqa0JbhnY3Dc3FVtZfe +P+s2Cyep3pVKvFer2llRoGm8TwraG5Yhyx8Oq/1qETpstjbURJOVBLDCV4AjOEUj0ZnE/tEo/DK yexgGaViNvjp+IZdFdJhYmsVjw4Q3vG7O0pfsLiYEyQjeDgjNEWDfa5/MufPywIfxzCCBb8wggOn oAMCAQICAwI5qTANBgkqhkiG9w0BAQ0FADBUMRQwEgYDVQQKEwtDQWNlcnQgSW5jLjEeMBwGA1UE CxMVaHR0cDovL3d3dy5DQWNlcnQub3JnMRwwGgYDVQQDExNDQWNlcnQgQ2xhc3MgMyBSb290MB4X DTE0MDYxMjE2MzYxOFoXDTE2MDYxMTE2MzYxOFowfDEhMB8GA1UEAxMYQ2hyaXN0b3BoIEFudG9u IE1pdHRlcmVyMSQwIgYJKoZIhvcNAQkBFhVjYWxlc3R5b0BzY2llbnRpYS5uZXQxMTAvBgkqhkiG 9w0BCQEWIm1haWxAY2hyaXN0b3BoLmFudG9uLm1pdHRlcmVyLm5hbWUwggEiMA0GCSqGSIb3DQEB AQUAA4IBDwAwggEKAoIBAQDimE/+P29P11lP6Td98fG9FYw67MGe7k7cWXjLb5Yvukut8uISFbMZ eEe+NKqm3i8I1J2rLjfjneee7z6Exv64S2pIgvUAdTl4uG4M1U31Lhu30TucDZYpgFQsJSL/EIP8 YvtOjIk3CGuHNwJnuldJzfFWoWgLh/rB5T0TGGgRlA1GlMzQEUI6Lh9HG8oU2dRiCMqGrLRNrkfR fHzqYCnRDh3GgPuaEjmJMXpNGRSF4QvEXbgkK4B/Tgzz0LB+3oNEfUWknfK+BbYHlTloVIvhmcXg 3/DIIHsOSbWtDtEIC/Dlu2R/RV0+dTtxwMLHwcRzafEr+VsKOvOe+HexrUILAgMBAAGjggFwMIIB bDAMBgNVHRMBAf8EAjAAMFYGCWCGSAGG+EIBDQRJFkdUbyBnZXQgeW91ciBvd24gY2VydGlmaWNh dGUgZm9yIEZSRUUgaGVhZCBvdmVyIHRvIGh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzAOBgNVHQ8BAf8E BAMCA6gwQAYDVR0lBDkwNwYIKwYBBQUHAwQGCCsGAQUFBwMCBgorBgEEAYI3CgMEBgorBgEEAYI3 CgMDBglghkgBhvhCBAEwMgYIKwYBBQUHAQEEJjAkMCIGCCsGAQUFBzABhhZodHRwOi8vb2NzcC5j YWNlcnQub3JnMDgGA1UdHwQxMC8wLaAroCmGJ2h0dHA6Ly9jcmwuY2FjZXJ0Lm9yZy9jbGFzczMt cmV2b2tlLmNybDBEBgNVHREEPTA7gRVjYWxlc3R5b0BzY2llbnRpYS5uZXSBIm1haWxAY2hyaXN0 b3BoLmFudG9uLm1pdHRlcmVyLm5hbWUwDQYJKoZIhvcNAQENBQADggIBAF59y2IuAaV7ltqym6jP IDiTtSntJWEYduJ/qlB+gVz/1OHH0Zedilf5Trg8zJYF9bAdkjLnZWDRFWS8+LW3qaIbIF+hKkLq ihHRspa1QiiDD/KaopaVMtVHyRsupGZGTiO4y0JcbYrfIzKBf+uOS5RK4WPYGOmSbOAK0yiNtQxh uzN4+aFDsMnrZgR20qlyM33hACwjkZaUgBuzcolrMBxo0JEl5cItxQxyHIockD41cflrP96QHEEw HMk/YCfbQ8/zxQjglbXzPfUqIb1RUZra47iXhpaBV7YaeE0R0IP+jjyawkRYoC3m+XbIyqvuKGY0 +hxTb78VbTE97+9+105MP2mBd1IZ/imt0P7berZi+lqU4LOvanzIIlk1UE8zEA/iYvTc4SS1fNrj CiGoCZx5cp8ZQ3BEYFo++0gac+ukuEJD7ZgkODyDVQSyTbdsrJmUlZ4onJWo4GwMmaNoGw3+oqFA Wdq/7NB2oaEx5pKKwX/neYPeDJViDYlGXXxqmAZuDfaTIuaiaprQluGdjcNzcVW1l974/6zYLJ6n elUq8V6vaWVGgabxPCtobliHLHw6r/WoROmy2NtREk5UEsMJXgCM4RSPRmcT+0Sj8MrJ7GAZpWI2 +On4hl0V0mFiaxWPDhDe8bs7Sl+wuJgTJCN4OCM0RYN9rn8y58/LAh/HMIIGCDCCA/CgAwIBAgIB ATANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3 LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG 9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0wNTEwMTQwNzM2NTVaFw0zMzAzMjgwNzM2NTVa MFQxFDASBgNVBAoTC0NBY2VydCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcx HDAaBgNVBAMTE0NBY2VydCBDbGFzcyAzIFJvb3QwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIK AoICAQCrSTURSHzSJn5TlM9Dqd0o10Iqi/OHeBlYfA+e2ol94fvrcpANdKGWZKufoCSZc9riVXbH F3v1BKxGuMO+f2SNEGwk82GcwPKQ+lHm9WkBY8MPVuJKQs/iRIwlKKjFeQl9RrmK8+nzNCkIReQc n8uUBByBqBSzmGXEQ+xOgo0J0b2qW42S0OzekMV/CsLj6+YxWl50PpczWejDAz1gM7/30W9HxM3u YoNSbi4ImqTZFRiRpoWSR7CuSOtttyHshRpocjWr//AQXcD0lKdq1TuSfkyQBX6TwSyLpI5idBVx bgtxA+qvFTia1NIFcm+M+SvrWnIl+TlG43IbPgTDZCciECqKT1inA62+tC4T7V2qSNfVfdQqe1z6 RgRQ5MwOQluM7dvyz/yWk+DbETZUYjQ4jwxgmzuXVjit89Jbi6Bb6k6WuHzX1aCGcEDTkSm3ojyt 9Yy7zxqSiuQ0e8DYbF/pCsLDpyCaWt8sXVJcukfVm+8kKHA4IC/VfynAskEDaJLM4JzMl0tF7zoQ CqtwOpiVcK01seqFK6QcgCExqa5geoAmSAC4AcCTY1UikTxW56/bOiXzjzFU6iaLgVn5odFTEcV7 nQP2dBHgbbEsPyyGkZlxmqZ3izRg0RS0LKydr4wQ05/EavhvE/xzWfdmQnQeiuP43NJvmJzLR5iV QAX76QIDAQABo4G/MIG8MA8GA1UdEwEB/wQFMAMBAf8wXQYIKwYBBQUHAQEEUTBPMCMGCCsGAQUF BzABhhdodHRwOi8vb2NzcC5DQWNlcnQub3JnLzAoBggrBgEFBQcwAoYcaHR0cDovL3d3dy5DQWNl cnQub3JnL2NhLmNydDBKBgNVHSAEQzBBMD8GCCsGAQQBgZBKMDMwMQYIKwYBBQUHAgEWJWh0dHA6 Ly93d3cuQ0FjZXJ0Lm9yZy9pbmRleC5waHA/aWQ9MTAwDQYJKoZIhvcNAQEEBQADggIBAH8IiKHa GlBJ2on7oQhy84r3HsQ6tHlbIDCxRd7CXdNlafHCXVRUPIVfuXtCkcKZ/RtRm6tGpaEQU55tiKxz biwzpvD0nuB1wT6IRanhZkP+VlrRekF490DaSjrxC1uluxYG5sLnk7mFTZdPsR44Q4Dvmw2M77in YACHV30eRBzLI++bPJmdr7UpHEV5FpZNJ23xHGzDwlVks7wU4vOkHx4y/CcVBc/dLq4+gmF78CEQ GPZE6lM5+dzQmiDgxrvgu1pPxJnIB721vaLbLmINQjRBvP+LivVRIqqIMADisNS8vmW61QNXeZvo 3MhN+FDtkaVSKKKs+zZYPumUK5FQhxvWXtaMzPcPEAxSTtAWYeXlCmy/F8dyRlecmPVsYGN6b165 Ti/Iubm7aoW8mA3t+T6XhDSUrgCvoeXnkm5OvfPi2RSLXNLrAWygF6UtEOucekq9ve7O/e0iQKtw OIj1CodqwqsFYMlIBdpTwd5Ed2qz8zw87YC8pjhKKSRf/lk7myV6VmMAZLldpGJ9VzZPrYPvH5JT oI53V93lYRE9IwCQTDz6o2CTBKOvNfYOao9PSmCnhQVsRqGP9Md246FZV/dxssRuFFxtbUFm3xuT sdQAw+7Lzzw9IYCpX2Nl/N3gX6T0K/CFcUHUZyX7GrGXrtaZghNB0m6lG5kngOcLqagAMYIC7TCC AukCAQEwWzBUMRQwEgYDVQQKEwtDQWNlcnQgSW5jLjEeMBwGA1UECxMVaHR0cDovL3d3dy5DQWNl cnQub3JnMRwwGgYDVQQDExNDQWNlcnQgQ2xhc3MgMyBSb290AgMCOakwDQYJYIZIAWUDBAIDBQCg ggFjMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MTIxMjIyMTUz OFowTwYJKoZIhvcNAQkEMUIEQNdE9Pj+HWbxDYRPjZ2P8fWH/slIbBoCy8vU0IWExlECe8LoBo4h GcJQuy2pFJ+clUhd/9un9PeCaE4TNUnLzQMwagYJKwYBBAGCNxAEMV0wWzBUMRQwEgYDVQQKEwtD QWNlcnQgSW5jLjEeMBwGA1UECxMVaHR0cDovL3d3dy5DQWNlcnQub3JnMRwwGgYDVQQDExNDQWNl cnQgQ2xhc3MgMyBSb290AgMCOakwbAYLKoZIhvcNAQkQAgsxXaBbMFQxFDASBgNVBAoTC0NBY2Vy dCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcxHDAaBgNVBAMTE0NBY2VydCBD bGFzcyAzIFJvb3QCAwI5qTANBgkqhkiG9w0BAQEFAASCAQC5PlaNCdxwoJYL2MFVDqk65Yp4MZ1N MynOmJZKyeWw2vaCBEb6OeTLj/2Eu/kdR9nCpNQEIxE73qhFzKpKNOnJcc5IPQZk+zJ2jEgg3wMB 7HwCr2y2iuShK3DiatepMGYiXR+gcv+PBZEo0+rGDokJoP1LF7rvateqXRFoU4CVpdZ2faSuDCG8 Z7y9EDbLcsCl7zVR+Z9hn7Rb1YSPHVy1ueinblWXPYQn1GIdiF5vZxQdaXW964hr5WLRl6tCLS3M j8n4BKHe0ehIelMT6zr8VLsvobCeMcT9kmF3S5ehnESca7lfkQQEj9uJPM9V0wmHd2GZH5DTmNkj MY8lCwVkAAAAAAAA --=-vhErYdQMAdg/N3Kcj3VD--