Eliminate Google annoyances by relinquishing your privacy

May 28, 2007

Objective: avoid getting useless results from Google without giving up on your privacy.

Solution: unknown.

Rant: All right, so here I am, a Google user who values privacy. I don’t want to “personalize Google” – I prefer to Customize Google (see http://www.customizegoogle.com; allows you to anonymize Google cookies and block ads) instead and I set Firefox to wipe out everything (cache, cookies, history) upon program exit, which means I have to configure my search preferences every time I open the browser and visit a non-English Google site. Fair enough.
Does this mean they should serve me useless search results? I hope not. Search results can be tailored for whatever kind of cookie I get during each browser session, so if I click on English results 99.99% of the time, why is Google constantly high-ranking me non-English results I never click on?

Luckily the new Customize Google has a feature (Preferences > Sticky Google Preferences > Interface Language) that allows me to automatically access their English GUI and have Safe Search turned off. It’s interesting how these preferences stick around while the cookie is around, but the search engine doesn’t customize search results based on client’s clicking behavior. I guess the solution is to browse Google logged on to my Gmail account or use its personalized features. I think I’ll pass.

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Is iSCSI NAS SAN?

May 9, 2007

If you think the title makes no sense, read this post and other posts related to the original post.

Although this will automatically put me into the mind-losing group, from the sales and non-technical marketing perspective – note the emphasis – I tend to agree with his “politically incorrect” view of iSCSI. I doubt that any of these critics have ever spent hours – I have, and it wasn’t fun – pitching their solution to the customer only to be asked “Is this NAS thing of yours that SAN thing?”

From the NetApp perspective, I guess that iSCSI indeed is Network-Attached Storage Area Network-kinda Storage. Seriously, in simple terms, it’s just another way to allocate NetApp storage to clients/hosts. Because NetApp filers are versatile (NAS, iSCSI, SAN), they don’t really need to care or argue about this with their prospects and/or customers. (Personally I think there’s a better way to provide a single solution for integrated block and file storage – more about this some other time).

Says Marc Farley:

It does not matter if the network is Fibre Channel or Ethernet (or carrier pigeons), the network is simply a way to transmit information for a storage application.

Well, this is exactly why I do not equal iSCSI with SAN. It does matter. I don’t have anything against accessing my database over FC (as long as I can afford it). And yes, in some cases I would definitively consider recommending Ethernet instead, but I would never recommend or even consider using PTP (Pigeon Transport Protocol). (Not yet, anyway. Maybe one day we’ll have storage-enabled pigeons that will be able to use spooky action at a distance to overcome limitations of PTP v1. Even with PTP v2 we’d still need a good MPIO mechanism for pigeons to prevent Single Point Of Flying, or SPOF – it’s gonna take time.)

When people hear “SAN” many of them will – maybe mistakenly, as this SAN could be Ethernet-based – visualize thin orange cables, low (lower than GbE) latencies, dedicated FC storage switches and the rest of FC-SAN h/w and s/w. I am not saying that Gigabit Ethernet and iSCSI won’t or can’t do, but it’s just not the same. What I am saying, though, is that this isn’t any more PC and/or less confusing than Dave’s opinion.

iSCSIs vendors would like you to think iSCSI is SAN and Ethernet is as good as FC, versatile storage vendors say “whatever you want, pal”, and so on and so forth. It’s (not) that simple! Devil said (not actually, but in a movie): “Consider the source, son!”

If we wanted to be technically correct or very PC from the technical point of view, we couldn’t easily communicate with decision makers and other stakeholders (assuming that everything offered satisfies requirements from the customer’s RFP, why would application owner have to care what’s happening behind that mount point?), which is why occasional technical heresy can be a skill.

P.S. By the way, whatever happened to IP-SAN? It’s been a while since I heard iSCSI vendors using this term. Did it have to go because it had a low-end (as in “Netgear launches dirt-cheap IP SAN” Ouch!) ring to it? That’s too bad, because I kind of like it and it means what it does.


Good Riddance, Filesystem Consistency Check

May 5, 2007

An old ZFS hand shared with us two simple ways to improve performance of your (production) ZFS filesystem, one of which is to “disable ZIL”. And what is ZIL?

The ZIL is the way ZFS maintains consistency until it can get the blocks written to their final place on the disk.

As we all know, disabling stuff that has to do with consistency checking is not a good idea.

Hopefully no reader left the page without reading the comments, because one of them contains a life-saving advice:

Also, you should not turn off the zil. If your storage device has a non-volatile order-preserving cache, then you can safely turn off the flush write cache command by setting zfs_nocacheflush=1 in /etc/system.

Oh, o-kay!

Obviously this kind of “tuning” is quite popular – why spend money on crappy (insert your most hated storage vendor of the day) storage when you can tune your filesystem instead?

> There’s actually a tunable to disable cache flushes:
> zfs_nocacheflush and in older code (like S10U3) it’s zil_noflush.

Yes, but we didn’t want to publicise this internal switch. (I would not call it a tunable). We (or at least I) are regretting publicising zil_disable, but using zfs_nocacheflush is worse. If the device is volatile then we can get pool corruption. An uberblock could get written before all of its tree.

It seems there are still dream jobs out there and I was badly mistaken when I thought “get paid to play around with company data” would be false advertising.


WordPress Autosave Feature

May 5, 2007

Recipe for Disaster

  1. Open your Dashboard in two browser windows (or tabs).
  2. Pick one of them, click on Write > Write Post and start writing your post. Put some random character in Title (e.g. “osf/”), as if you mistakenly pasted some characters there.
  3. Go back to the other window, pretend you don’t remember your post Title in the other window (or that you had that other window open) and you’ll see this weird draft post osf/). Huh? Delete that garbage. You can close this window (or tab) now.
  4. Now continue editing your post in the other, surviving window. Your draft will be auto-saved regularly. You can also change  your post Title from osf/ to Something Smart.
  5. When you’re done with writing, hit Save. Congratulations – Page Saved, says WordPress!

I’ve got some bad news for you, dude – your post is gone! And no, going Back in your browser won’t help you.

Yeah, I know I deleted my own post, but why the heck is my Write Post page lying to me that my page has been saved?


New Computing Architecture

May 4, 2007

Interesting blog post at ZD IT Link:

“The chief architect of IBM’s systems thinks the industry is on the cusp on creating new computing architecture that will allow applications to run some subset of their operation on top of storage servers rather than compute servers.”

Okay, so you run some application code on pSeries and xSeries servers and some on IBM N Series (NAS filers OEM-ed from NetApp). What applications, except NDVM backup, run on NetApp’s OnTap OS? I don’t know of (m)any. Then where does N Series fit into this new architecture?

“According to Rod Atkins, IBM is building prototypes of hybrid systems that will allow portions of a database to execute directly on a storage server powered by a P series processor.”

Oops, it looks like it doesn’t. If they keep reselling NetApp, won’t IBM end up with two storage server solutions – the absolutely proprietary N Series and the relatively proprietary pSeries?

This doesn’t sound like unified storage to me: N Series for serving file, iSCSI and FC storage and pSeries storage servers for executing “portions of a database”. I hope they won’t make pSeries storage servers use storage provisioned by an N Series filer, that would be a little too complicated!


A New Beginning

May 3, 2007

Isn’t “a new beginning” a nice example of contradictio in adjecta? Yet you’ll find over 1.4m instances of it on Google.

This is a v2 of the first post – the first got lost because while editing I cleaned my browser cookies which made “Save and Continue Editing” fail. Logging on again didn’t help save the original post. Some new beginning!