what the largest number of any shares anyone's currently exporting from a toaster?
In ONTAP releases prior to 4.3, we had an upper limit that amounted to about a thousand shares in a typical configuration. The actual limit was "fuzzy", because it wasn't defined by any hard, static configuration that directly limited the number of shares to a certain specific number. It was defined by an internal buffer pool and some semantics that were specific to the algorithms that managed the use of those buffers when Windows clients attempted to enumerate a filers shares. To give you an idea of what I mean, you could actually create quite a few more than 1000 shares using these older versions of ONTAP, as long as you kept the comments you placed on those shares to a minimum (making them either short or non-existent). The up-to-32-character share comments that Windows allows you to associate with shares used up space in these buffers that would otherwise have been usable to define more shares in! :-)
However, as of ONTAP 4.3.3 and beyond, this way of doing things ceased to exist. The upper limit on the number of shares a filer can export is currently a function of the amount of memory you have installed. On the F5XX and F6XX filers, you're looking at a limit of:
2400 + 2000*(# of 64MB chunks above 128MB)
and on the F2XX and F3XX the numbers are ironically even higher due to a difference in the size of memory addresses used by the CPU's we use in the lower end filers versus the CPU's we embed in the higher end filers.
Bottom line, we're talking about a veritable truckload of shares here. When the limit used to be around a thousand, I only knew of two customers who "discovered" it. Oh... I should probably mention that these limits are not inclusive of the automatic shares that are generated on the fly for individual users when you set the:
options cifs.home_dir /wherever/whatever
option. In other words, these *don't* count towards the total, and these could potentially amount to thousands more shares than just the statically defined ones.
are there performance penalties associated with too many shares,
No, unless you count the amount of time it takes to enumerate the things (that's the amount of time you have to stare at the torch (flashlight) scanning backwards and forwards after you have double clicked the filer under "Network Neighborhood"). However, whatever amount you've created, I think it's a pretty safe bet that Data ONTAP will spit 'em back at you more rapidly than NT would given the same number. ONTAP has a rather tight focus on the such matters. :-)
Keith