Date: Fri, 9 Jul 1999 04:42:30 -0400 (EDT) From: Robert Watson <robert@cyrus.watson.org> To: John Barbee <jbarbee@singular.com> Cc: freebsd-afs@freebsd.org Subject: Re: please clarify: afs and dfs and other fs Message-ID: <Pine.BSF.3.96.990709043106.24202E-100000@fledge.watson.org> In-Reply-To: <4.1.19990708123047.00a387b0@server7.singular.com>
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David answers most of your questions, but I thought I'd interject a few comments here and there based on my own experiences. On Thu, 8 Jul 1999, John Barbee wrote: > Hi, > I'm doing a little bit of research for a project that we may undertake in > the future. A lot of what we want to do is based around a reliable > distributed fs architecture. We've heard that IBM uses a lot of AFS for > their e-commerce, OSS-related stuff. I'm actually not that familiar with > IBM's practices, but that's what I'm told. > Anyway, I read through the AFS FAQ and it seems to be something we can > use. However, I new to the different distributed file systems > architectures and don't understand certain things around AFS and hoped that > someone could clarify them. > According to AndrewII, AFS has been replaced by DFS from OSF. When I go I believe that the decision has been made to stick with AFS, at least for the time being, based on the fact that Transarc made a formal policy decision to continue supporting AFS, and that AFS clients have become available for the Windows platform. One of the stated goals of AndrewII was to make Andrew more compatible with a single-user windows-style networking environment. AFS originally did not fill this niche, but noe does. > to OSF's website there is no mention of DSF. On a different note, I > thought DFS was a Microsoft product. Besides that, why are people working I have seen Microsoft literature referring to their upcoming distributed file system as DFS, but DFS is more appropriately used to refer to the DCE file system, and Transarc is a producer of the file system. Their web page should provide more details. > on Arla (by this I mean make free versions of AFS instead of DFS) or > porting AFS if it has already been replaced? AFS is still quite alive and kicking: the availability of the Arla client has played a part in this. The proposed free Arla AFS server should have enourmous impact. Assuming that the free AFS server becomes available, I see AFS as the direction of choice for all the environments I work in--AFS has tight integration with Kerberos, multi-platform support, scalability to a global level, etc, etc. Throw in a little public key infrastructure and things should be really pretty :-). > Lastly, is this in any way related to CODA or CIFS? As David mentions, Coda is a further research file system attempting to address mobile and fault-tolerant computing. It is based on the AFS2 source code, released by IBM for this purpose. Originally it was under a CMU license (close to BSD, except more like the 2-clause version, and with an appeal for contributions of modifications while not requiring it.) Unfortunately, it is now under a GPL license, although a number of the supporting libraries are under LGPL. The code is still experimental, and lacks stability and scalability. It does support write-replicated file servers, while AFS supports only read-replication at this time. Similarly, it has disconnection support: i.e., the ability to continue working out of the cache when connectivity becomes poor, and to replay logs of modifications and help resolve conflicts on reconnection. Coda has great promise, but I believe it has a long way to go before attaining a level of stability appropriate for production environments. The disconnection support in Arla is rapidly coming up to speed, and with a few more tools will be quite sufficient :-). Arla also has the advantage of being under a BSD-style license from KTH, and being quite stable. We'll see how things go as a server product becomes available. I believe Arla supports all the security features of Transarc's product, but that that is limited to Krb4, and hence single-DES. Coda in its base form has little or no cryptographic security, but my crypto patches add in support for strong crypto algorithms and also kerberosIV and kerberosV support. Only the kerberos patches are currently available as I'm still cleaning up the crypto stuff, and currently outside the US so can't work on the crypto stuff remotely :(, as that might count as export. Presumably once Transarc and Arla support KrbV, support for additional algorithms will be straight-forward. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Computing Laboratory at Cambridge University Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-afs" in the body of the message
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