On Mon, Jun 24, 2002 at 08:12:50PM -0700, Art Hebert wrote:
Having never been able to to attend Netapp classes, bear with me if these are fairly simple.
- CIFS was purchased but never actually used. It currently shows up when
you type license. Will this in anyway affect the Netapp nfs performance?
Shouldn't. If you aren't using it it should just be a licensed feature.
- Does disk scrubbing run automatically daily and if so is this
changeable, by day, by time?
Scrub is every Sunday morning at 1am. You cannot change the date and time on the automatic scrub BUT you CAN turn scrubbing off and scrub using a cron job to start the scrub.
- Can somebody give me the rundown on running wack? This is what I have
off the net (somehow the this is how you do it part never got published).
wack is now called wafl_check. You have to take the volume offline to run this. The only time I have ever had to run this is on advice from NetApp support. Good info from Dave Hitz.
When to use WACK on a NetApp Filer
From an email by Dave Hitz (12/1999) on the Toasters mailing list.
The main difference between "wack" and fsck or scandisk is that you shouldn't need to run wack during normal operation. In particular, unlike UNIX and NT, you don't need to run "wack" after a system panic, or when you pull the plug without shutting the system down, or after a power failure. The WAFL filesystem uses a database technique called "shadow paging with NV-RAM log replay" to maintain a fully consistent state on disk even in the face of unexpected shutdowns. So when do you need to run wack? Suppose that you have a disk fail in RAID, and then when you try to reconstruct the data from the lost disk you discover that there is a bad sector on one of the other drives. Most of your file system data is just fine, but you've got a couple of blocks that can't be recovered. The RAID subsystem zeros both blocks, since that's the best that you can do, but now you need to run wack in order to fix things up, in case the zeroed blocks contained file system data like inodes, indirect blocks, or the free block map. And yes, I must confess that like any computer, NetApp systems do contain the occasional bug, so WAFL has a number of checks to make sure that the on-disk data looks reasonable, and if it finds a problem it will ask you to perform a wack. Our goal is for customers never to need to run wack, but the reality is that people sometimes do need to use it. this is how you do it.
Thanks
art hebert