I am generally fairly negative on hardwareRAID; I feel that both in theory and in especially in practice, it isalmost never a benefit. However, today I realized that there is oneway that a hardware RAID card could have an advantage: avoiding PCIbandwidth limits during RAID reconstruction.

In the general case, RAID reconstruction has to read all of theremaining intact disks and then write back to the new disk. Withsoftware RAID, this data must cross the PCI bus, since it is theserver's

We have two categories of machines here; let me call them appliancesand systems. Systems are machines that users have access to or thatprovide complex, general services to the Internet; our login and computeservers, our IMAP server, and so on. Appliances are not user accessible,are more or less hermetically sealed, and generally only expose thespecific service that they're supposed to provide.

We keep systems up to date on patches. We have to; they're exposed. Butwe almost never patch

Recently, I've started actually doing things with my Facebook account,and I've done a bit with Twitter, and of course I've used LiveJournalfor a while now. All of which, especially Facebook, has recently givenme a bit of additional perspective on something.

You know all that stuff that I wrote aboutwhat makes social networking sites sticky? Sure, it's accurate as far asit goes, but I missed a big bit of it: time. Namely, the sheer amount

One of the ways that Solaris does not make me happy is that they donot seem to have changed various system defaults since, oh, 1996, whenmachines were much smaller than they are now. As a result, we haveaccumulated a set of NFS server parameters that we have had to change inorder to get decent performance and functionality.

(This set is not particularly novel, which is part of the irritation;pretty much everyone winds up making many of these changes sooner orlater. But

Presented in the traditional illustrated form:

; cat arootcks; cat brootcksabc; comm -13 a b >/dev/nullcomm: file 2 is not in sorted order

If your comm doesn't do this, don't be surprised; this behavior is newin the very latest version of comm , from coreutils 7.2 (as installedon Fedora 11; Fedora 10 didn't have it). This behavior is turned off bythe new --nocheck

Here is something that I've alluded to before : email is quite intrusive (well, at least in my branch of the world).For both technical and social reasons, email messages are far more like(work) phone calls than they are like paper mail.

On the technical side, you get a lot more email than you do paper mail,and it's harder to scan and sort your email than your mail. For example,most paper mail is loaded with cues as to what sort of

Suppose you have a piece of hardware where the mapping between BIOSdrive numbers and Linux device names is not straightforward, and youwant to figure out just what the mapping is (at least for your currentdisks). If you use GRUB (and you probably do), there's a relativelysimple way of doing this.

GRUB has two important attributes for this: it can read Linuxfilesystems and tell you what's in them, and at boot time it is workingwith the BIOS drive numbering. So

I just upgraded my office workstation from Fedora 10 to Fedora 11 viapreupgrade, one of the two officially supported ways of doing it. Ittook four hours. Of course, my machine was effectively down for thosefour hours, as it was off the network and unusable.

(While my office machine has a lot of RPMs installed (2742 after theupgrade), it is not a slow machine, so I suspect that this is not anunusual thing.)

I know, Fedora doesn

Suppose that your machine is an NFS client, and it periodically logsa kernel error message that looks like:

nfs_stat_to_errno: bad nfs status return value: 16

What does this mean?

The short summary is that your NFS server is violating the NFSspecifications. NFS requests can fail, and when they do the serverreturns an error number to tell the client why. The NFS specs say whatthe allowed error numbers are; the Linux kernel client code checksthat the error number it got