Sysconfig's Blog

ZFS on FreeBSD 7 — experimental for a reason!

Yes, it has a reason that ZFS is not yet marked stable on FreeBSD! I had to learn the hard lesson today.

Under very high load and many concurrent read requests (I set up the company’s mail server with ZFS and root from ZFS), the two disks in the Raid array repeatedly lost sync, forcing an automatic re-silvering (auto healing) process to be started, which blocked the system as everything (except /boot) was running from that ZFS arrray. As far as I figured out, the system halted entirely as there was another inconsistency occuring while the re-silvering was still in progress.

I would have investigated further, if it wasn’t a crucial production machine. And that kind of traffic is very difficult to simulate under laboratory situations (maybe I can do that when I have more time). So I had to revert back to UFS as the downtime had to be minimized. It’s a shame, really, because I love the features ZFS offers. On my private server it runs very smoothly, but traffic, load and I/O are not comparable to the mail server in question.

Posted in BSD, Storage, Work | No Comments »

SPF — Sender Policy Framework

Did you ever receive spam mails which seem to originate from your own mail address? Or did anybody else complain about you sending those emails? Then you should take a look at SPF. In a nutshell, it plugs the holes in the SMTP protocoll, which does not allow to verify if a sender (or anybody who pretends to be that sender) really may use a particular mail server to transmit their mails. Unfortunately, SPF is not yet very wide-spread. Almost everybody (including me) has come across this abbreviation and/or heard that it might protect misuse of mail addresses. But most people (including me) cannot be bothered to implement it.

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Posted in general, Software | No Comments »

Two neat storage machines

Yesterday I set up one of our new storage machines for testing: Dell 2950, Quad Xeon, 8GB, 6×750 GB HDD. I installed FreeBSD 7 with ZFS (following up this article). Firstly it seemed to be a bit tricky, because the PERC/6i controller configuration is — sorry — crap from the usuability point of view. It seemed not to support non-RAID configurations, but taking a closer look it turned out to be a wrong assumption. Six RAID-0 Arrays with only one drive each is in fact the same as no RAID at all. (The reason why RAID does not make sense is, that ZFS will do this job, and its auto-healing is much better than any hardware controller’s auto-healing)

After having set up the minimal FreeBSD and doing some tuning (such as creating the ZFS volumes), I ran some tests. You won’t believe me, but writing a 10GB file (/dev/random to the ZFS volume) resulted in a transfer rate at about 160MB/sec and reading (cp testfile /dev/null) was done at a speed of more than 270MB/sec!!

To be continued…

Posted in BSD, Storage, Work | 2 Comments »

Solaris’ ZFS on FreeBSD 7.0

Wasn’t it annoying that FreeBSD never had a volume manager which allowed to resize volumes including the contained filesystem on the fly? Well, it was possible to use gvinum in conjunction with UFS’ growfs tool to make filesystems bigger at least. But that’s not as flexible as Solaris’ ZFS. Moreover, UFS does not support snapshots as well as ZFS does. But finally we have a solution: Since FreeBSD 7.0, ZFS is part of the OS! Although it is still considered experimental and lacks some of the original’s features, it works quite well. Also, it is possible to use ZFS as a boot partition! See this great article.

Posted in BSD | 1 Comment »

(C|G)lustered Storage

As the company I work with has to store many media files, backups, rapidly changing documents and so on, they used to run a NetworkAppliance FAS2020 storage machine, which is quite neat. Unfortunately, the current setup does not allow to scale the volumes any more. So we needed to find an alternative.

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Posted in BSD, Storage, Work | No Comments »

Syncing calendars on multiple Macs and Nokia N95

Generally it is quite easy to sync calendars between one Mac and a Nokia N95 (or any other model). All you need is iSync and the Nokia iSync Plugin. The setup is quite straight-forward. But as the computers store the synchronisation information, conflicts are very likely to happen. So we need another solution to keep two (or more) computers and a mobile phone in sync.

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Posted in Mac OS, Software | 1 Comment »

How I started to love Mac

To be honest, three months ago I could not imagine that I would fall in love with Mac OS and/or Apple’s products. I considered them way too expensive and did not understand the hype, because technically they do not differ much (any more) from i386 hardware. But as my new employer offered to provide a MacBook Pro for my daily business, I thought: “Why not?”

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Posted in general, Mac OS, Work | No Comments »

Welcome to my blog

Yes, another more or less useful blog, I know

In fact, this blog is not about one certain topic only. It will represent “snapshots” of my work and experience as a Systems Administrator, clearly focused on Linux/BSD and Mac OS X (the latter rather from a user’s than a Systems Administrator’s point of view). I should have started this blog years ago. Anyway, it is never too late to contribute to the community. If there are any other bloggers out there, who are interested in linking this blog, please let me know.

Posted in general | No Comments »