Hi Chris,

Sorry it's taken me a while to reply. I'm very interested in your take on the Solaris 9 du patch, as I was instrumental in its creation.

One of the customers I work with at NetApp had noticed that du returned a "cycle detected" error in Solaris 9, whereas it had not in Solaris 8. (Incidentally, I'm told Solaris 10 doesn't return this error either). With the help of my customer and Sun, we were able to identify the code change which had provoked this behaviour.

As I understand it, Sun's patch does indeed, as you say, revert to the earlier Solaris 8-like behaviour, in that it ignores the error condition rather than fall over when it hits it. (Although Sun themselves are far better placed to comment than I am). This is what the customer in question wanted from the patch.

Unfortunately I will be out of the office all of next week (back on 7th February), but I'd be happy to discuss this further with you when I return. My customer, I'm sure, would also be most interested to hear what you think of this solution, as so far he appears to be the only one to have reported this issue to us - unlikely as that sounds.

Please feel free to drop me a line or give me a call.

Regards,

Simon.

Simon Barnes Technical Global Advisor (TGA) Network Appliance simonb@netapp.com Tel +31 (0)23 5644262 Mobile: +31 (0)655 773100

-----Original Message----- From: Chris Thompson [mailto:cet1@cus.cam.ac.uk] Sent: Thursday, January 20, 2005 12:37 PM To: toasters@mathworks.com Subject: Solaris patch 118463-01, NetApp filers, and du

I posted an article about this in the comp.unix.solaris newsgroup back in early December, but I didn't get any response. Maybe I will have more luck here.

A patch 118463-01 was released by Sun for Solaris 9 du(1) on 2004-12-06. It "fixes"

5068958 Solaris 9 du exits with "cycle detected"

The description of this on SunSolve includes the following:

| Description: | | Solaris 9 du exits with: | | du: failed for /: Cycle detected from XXX to XXX | | when a hardlink in the filesystem is detected. While at first sight | this seems reasonable behaviour due to the potentially harmful nature | of hardlinked directories, there is a genuine need to handle this in a more graceful way. | | One such example comes from using a NetApp File Server with snapshots. | The NetApp server exports snapshot heirarchies with file ids (aka | inode | numbers) which appear to be identical to existing directory file ids. | | While this is an implementation issue concerning the interaction | between Sun's NFS clients and NetApp File Servers, in the interests of

| interoperability, the Solaris 9 du should simply ignore directories | with apparent duplicate inode numbers.

I wonder what other users of Solaris in conjunction with NetApp filers think of this? Personally I thought the change in Solaris 9 was positively beneficial ... an error (even if obscurely expressed from the end-user's point of view) rather than a totally misleading result.

It might have been useful if the patch had been to produce warning messages "I've seen this directory inode number before, I'm leaving this [snapshot] out of the space calculation altogether" and carry on with the rest of the tree. (One might think that this was what was implied by "simply ignore directories with apparent duplicate | inode numbers".) But it seems that it actually restores the Solaris 8-and-earlier behaviour, in which you get a total which is a naive sum over all snapshots, which is never (well, hardly ever) meaningful.

Chris Thompson Email: cet1@cam.ac.uk