From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1BDA0m-00069v-DV for user-mode-linux-devel@lists.sourceforge.net; Mon, 12 Apr 2004 15:34:40 -0700 Received: from noxmail.sandelman.ottawa.on.ca ([205.150.200.166]) by sc8-sf-mx2.sourceforge.net with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.30) id 1BDA0l-0004yf-Kt for user-mode-linux-devel@lists.sourceforge.net; Mon, 12 Apr 2004 15:34:39 -0700 Subject: Re: [uml-devel] A quick humfs HOWTO In-Reply-To: Message from Nuno Silva of "Thu, 08 Apr 2004 07:25:22 BST." <4074F052.20603@vgertech.com> References: <200404080207.i3827rbe009294@ccure.user-mode-linux.org> <4074F052.20603@vgertech.com> Message-ID: <7394.1081782300@marajade.sandelman.ottawa.on.ca> From: Michael Richardson Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Mon, 12 Apr 2004 11:05:00 -0400 To: Nuno Silva Cc: user-mode-linux-devel@lists.sourceforge.net -----BEGIN PGP SIGNED MESSAGE----- >>>>> "Nuno" == Nuno Silva writes: Nuno> In the meanwhile I'm thinking about this system and it seems Nuno> that this will eat lots of inodes because every file will be Nuno> present twice in the [host] filesystem with the metadata Nuno> version using only a few bytes. Also every "ls -la" (if it's Nuno> not cached) in UML will generate a read in the file's metafile Nuno> file (say this 3 times quickly! eheheh). With 1000 files in a Nuno> directory thats lot's of fopen()s. Yes, this concerned me too. Nuno> Wouldn't it be better to add support for a simple DB, like Nuno> sleepycat or CMU cyrus' project skiplist or even something Nuno> lighter? This way we can have only 2 files in the humfs Nuno> "root", the superblock and the metadataDB. Yes, we should the option of doing that, also of having a .db file per directory. There should *ALSO* be a default. If we can store the information on the plain host, then don't put any metadata there. A directory should be able to say, "everything below is mode X" - this might also be useful for adding more detailed restrictions. Nuno> This can save inodes and improve performance because you have Nuno> only one file that's indexed! :-) Nuno> The downsides: - - another linker requirement at build time; - Nuno> - can't inspect and/or easily modify permissions with Nuno> emacs. :-) Yes/no. If we do it right, the file can be created with "makemap" or some such. Last I looked .db files have poor locking semantics. I'm trying to think about the situation where hostfs stuff is shared by multiple UMLs. (For instance, I share all of /usr/share...) - -- ] ON HUMILITY: to err is human. To moo, bovine. | firewalls [ ] Michael Richardson, Xelerance Corporation, Ottawa, ON |net architect[ ] mcr@xelerance.com http://www.sandelman.ottawa.on.ca/mcr/ |device driver[ ] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); [ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) Comment: Finger me for keys iQCVAwUBQHqwGoqHRg3pndX9AQFA1AQA0l52UOBFkCC3MvrnNLXBEXMs4gFsXmiq B6WLaUWOayX7Z7zmscARbPmRyBdKXpjcSHjuTMPHwnoYmVVC6RGiBSNOHeUGEhfZ 4wHSwJwRFbhlM/KYTsTmmVRirGwROpVSAOrHJY+3SyQ8Z9vMLkxnucEe60nF05GS STH551mEpAs= =AYWh -----END PGP SIGNATURE----- ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel