FSF Windows 7 sins

I don't normally post political messages here, but this one's important, I think.

The Free Software Foundation has posted 7 Windows 7 "sins" at http://windows7sins.org/, and I think they left out what in my mind is the most important issue. It's sorta covered in "Corrupting Education" and "Lock-In", but not really:

With Windows 7 (and Office 2003 before that, and Vista before that, and XP before that, and Windows 9x/W2K before that) users will have to retire/obsolete all of their existing training in the Windows user interface in favor of the newest cosmetic decisions Microsoft has made for its products.

I don't argue that there aren't significant productivity benefits to the current Windows shell (vs. Program Manager in NT and 3.x) or in the improvements from '95 to XP. I haven't seen much of Vista's Aero, or the new Windows 7 UI, and I'm sure all of the changes have been run by major interface testers.

But when I switched from Office 2000 to Office 2003, I had a rather steep learning curve to deal with the "Ribbon" UI. Even though I taught Office 97 to Computers 101 users in grad school (and was able to take that through to O2K) I was lost with the new "Where the h*** did the menu go" interface. (Ok, If I were an Excel developer, would I consider search&replace General (Home) thing, or a Data thing. It used to be in the Edit menu... )

But I relearned. And I was able to relearn because as I was growing up, the UI changed dramatically (from Write on my Apple ][+ to PC/Word Perfect to WPfW to vim/TeX and on to MS Office*) But for someone who's used to and has memorized the keystrokes/mouse clicks to insert a text box, this is a whole new ballgame.

When I was applying for jobs after college for example, one of the companies asked that I take an "aptitude test" which included things like typing speed and accuracy, formatting documents, generating mail merges etc. This computer-based test was graded on if you click the right menu option first. If you picked "Edit" instead of "Tools" (or if you right-clicked and chose "Format") you got the question wrong. Not that this was a good test, but it's typical for the industry. And the answers completely changed when 2K7 came out.

Of course, in my line of work, we're more concerned about the OS than about the Office apps. So it's things like the changes in networking that annoy me about Vista. Wow, the way I set up a dialup connection has changed. Hmm, I wonder what happens if I right-click here... etc. So I have to learn a whole new way to fix things that go wrong. Not to mention that Vista Home is quite different interface-wise than Vista Business.

And I'd expect that the various Windows 7 editions will look different too. After all, would the wizard that helps gramma connect to the wireless internet at Starbucks be the best way for IT professionals to diagnose an 802.1x authentication problem? If I learn how to do it with my home PC, will that apply to the real business world?



Netapp - Waster of space

We have a Netapp that we use to provide Tier-2 LUNS to our SAN. It was price-competitive on raw disk space, but I didn't realize at the time just how much overhead this appliance had.

The obvious overhead is RAID-DP and hot spare drives. Easily calculated. 1 HS per 30 drives of each size. DP is 2 drives per plex, so that's 6 wasted drives out of the 28 in two shelves, leaving 22 * 266GB drives usable = 5.7TB.

I'd heard that space is reserved for OS and bad-block overhead (about 10%) so that brings us down to 5.2TB usable.

Well, the web interface shows the aggregate as 4.66TB. So that's 600GB I haven't accounted for. But still, 4.66 TB is a good amount of space.

From the aggregate, we create a flexvol (note that this places 20% by default as inaccessible snap reserve space). On the flexvol, we create LUNs and present them to our servers. And here's where the space consumption is nasty:

By default, if you create a 1TB lun, OnTAP reserves 1TB of disk blocks in the volume. That's nice, and exactly what I'd expect. Although in practice, we use thin provisioning (lun create -o noreserve) for most of our LUNs

What I didn't expect going in was that the first time you create a snapshot, OnTAP would reserve ANOTHER 1TB for that LUN. And interestingly enough, that 1TB is never touched until there's no other space in the volume.

Ok, That ensures that even if you overwrite the ENTIRE lun after you take a snapshot. But it reduces the usable size of LUN-allocation to 2.33TB. And if you have multiple snapshots, those don't seem to go into the snap reserve, but rather are in addition to the 2*LUNsize that is already allocated.

So out of a raw disk capacity of (28*266) 7.2 TB (which is quoted as 28*300GB disks = 8.2TB) we get just over 2TB of space that can be used for holding actual system data.


Now, there are non-default settings that can change that, but they're only available at the CLI, not the web interface:

# snap reserve 0 - this will set the snap reserve from 20% to 0%, which is recommended for volumes that hold only LUNs.
# vol options fractional_reserve ## - This changes the % of LUNsize that is reserved when a LUN snapshot is taken.

It is not entirely clear what happens to a LUN when its delta becomes larger than the fractional_reserve. Some documentation says it may take the LUN offline, but I would hope that only would happen if there's no remaining space in the volume (like what happens with snapshot overflow in traditional NAS usages). But it's not clear.

As far as I can tell, the current best practice is to set the snap reserve to the amount of change you expect in the volume, and set the fractional_reserve to the amount of change you expect in the LUN. And to set up either volume auto-grow and/or snapshot auto-delete to make sure you have free space when things get full.

On the gripping hand, the default options make sure that you have to buy a lot of disks to get the storage you need.