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Re: 3 SysAdmin questions



On Thu, 1 May 1997, Tuvik Beker wrote:

> Hi, 
> 
> Three questions of varying complexity -
> 
> 1. I have the following problem: I want to share home directories in a
> network with hosts of different architectures, that were recently put
> together. Currently we have SGI and Linux, others may be added. The
> problem is to map the UID/GID spaces correctly. On a pure linux net,
> this could theoretically be accomplished by giving the 'map_daemon'
> option in /etc/exports to use ugidd for that mapping. However I think
> this is a security risk, and anyhow it doesn't apply to the mixed system
> in question. I think the right thing to do is maintain a central user
> database, with all the relevant parameters, and have each host access it
> to create its own /etc/passwd file, with unified UID/GID's.
> The problem (apart from how to do it properly...) is the silly group
> convention used by RedHat, which is unlike anything standard, POSIX or
> other. Do you think it would matter much if I abandon it and adopt a
> more conventional GID allocation? Does anyone have better ideas of how
> to accomplish the task? Bare in mind that each host already has its set
> of users, and some users have separate accounts on different hosts. The
> aim is to cause minimal disturbance while doing the merge.

NIS/NIS+ and AMD for mounting home directories.

> 
> 2. Any recommecdations as to a good backup tool for linux? Of course,
> one can simply write backup scripts to be run with cron, but I guess
> there should exist smarter applications, giving easy controll over
> multiple backups to tapes and disks etc. 

Please ask me that on private mail, since it's inside info of tel-aviv
universit, and I wont divulge it here. There is an answer, and I will give
it to you there. 
> 
> 3. There were threads in the past dealing with HD->HD duplication in the
> case of identical disks, and several solutions were suggested. What
> about moving an entire system to a larger disk? What is least likely to
> cause problems - tar|tar or dd (or cp -... ).
> Since this question comes up from time to time in one form or another,
> and at least some of the answers in the archives are incorrect, how
> about putting an authoritative answer in the FAQ? Does any guru
> volunteer to give the ultimate answer, or list the pros and cons of the
> various approaches? Marc, Evgeny, anyone else?!

Hmm, I have used tar in a few cases, and created exact copies. It didn't
even require the disks being the same size, or partitioned in the same
way. The problem with it is that it's slow(using pipes). cp -r is much
faster, I didn't try it though. About dd, I don't know, I am always
carefull with utilities that are raw-writing. Anyway, I am not in the
gurus lists you specified, but that is my experience with it.

--Ariel
 > 
> Thanks in advance for any hints or answers.
> 
> Tuvik
> -- 
> _______________________________________
>              Tuvik Beker
>         becket@shum.huji.ac.il
>  Tel. 03-5714436       Fax. 03-5334349  
> _______________________________________
> 

   +---------------------------------------------------------+
   | Ariel Biener                                            |
   | e-mail: ariel@post.tau.ac.il        Work ph: 03-6406086 |
   +---------------------------------------------------------+


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