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Brad 10-20-2008 02:06 PM

eSATA drive & using TC for non-VM backups
Hi Dave,

About to finally take the plunge and get a new MB 2.4Ghz or MBP 2.8Ghz (though if the MB Air had 4 GB RAM capability, I'd probably get that instead--which would reduce me to strictly USB 2 externally powered hard drives, but since I want 4 GB, that's all moot)... Thinking of my backup solution at the same time.

I'm gonna get a Time Capsule, so my wife's macbook (white) gets backed up automagically whenever she's on our wireless net at home (which she is all the time), as I can never seem to get her near a hardwire cable for SD!--though I'll still do an SD! backup when I can via FW400--probably weekly or every 2 wks. I'll have the TimeCapsule also backup everything OS X on my MB/MBP, but *not* my VMWare Fusion 2 VMs (see below). I assume I can tell TC to skip my VMs and just backup everything else, correct? (See summary of Qs below.)

As far as the MB/MBP goes, I plan on having several VMs on it, at least a Windows (for paying job) and a Linux (Ubuntu probably, maybe Open Solaris too, for startup I'm helping), so there goes at least 50GB, probably 80GB or more that will need to be backed up daily via SD!, plus changes to my OS X setup, of course.

If I choose the new MBP, I'm thinking for my SD! clone/backup drive, rather than FW800, why not just get an eSata ExpressCard34 like here:

Then hook it up to an enclosure like here:

At 3.0 Gbps, that'll blow away FW800, right? Do I need two cables to get the full 3.0Gbps? Not sure I fully understand how to get the 3.0Gbps throughput rather than 1.5 out of it...

If I need to boot off of it, *can* I do it via the eSATA, or would I then need a FW or USB connection (FW 800->400 cable for the above enclosure), meaning if I can't boot off the eSATA, I'd need to spring for: or (and if so, which of those two do you recommend?--if you'd rather not make a rec, I understand)...?

Sound good? I guess my main Qs around the MBP are:

(a) Can boot off the eSATA? -- also, how do I ensure I get the full 3.0Gbps throughput when backing up to it?

(b) is eSATA the way to go to make daily smart updates with SD! as painless as possible with a couple/three VMs changing often (Windows probably daily, the others at least 2-3 times a week). If so, do I need FW 800 for booting/recovery if internal laptop drive goes down and which of the two enclosures w/FW800 (Macally or OWC Mercury do you recommend if you have a preference--again, I understand if you prefer not to say)?

My rough calculations are that the eSATA solution would be about 7-10x faster than a USB 2 solution, and probably 3-4x faster than a FW800 solution, is that "about right" ? For possible 50 GB backups daily, that's significant... (I assume that changing Fusion VMs will incur the penalty to backup the whole VM each time they change at all.)

If I go with the much (rightly) maligned USB 2 only with the new MB I'll deal with the (much?) slower backups there. Also, related to both MB & MBP:

(c) *can I* tell TimeCapsule (TC) to skip my VMs so they don't get TimeMachined whenever I'm home? And is the 'drag' on the home wireless net (given that I'd only be on it once or twice a day at home M-F, with lots throughout the day on Sa-Su) make it not worth it to setup TimeMachine on my MB/MBP to the TimeCapsule for me (and just rely on my daily SD! backups instead)? IOW, should I just set up my wife's on TC, and not mine?

Related to (c): Do you know anything about the hourly TM (via TC, which is much slower) 'penalty' that is incurred over 802.11n wireless? Experimented with it much? (Don't want the wife simply frustrated that her machine 'slows down' every hour.)


dnanian 10-20-2008 02:13 PM

I don't think you're going to get nearly that throughput on a real backup, Brad, and from all reports the vast majority of eSATA drives/controllers do not support startup.

I've found TM backups over wireless to be extremely slow, but my configuration (which includes some large email folders, which change regularly, which is a pathological case for TM -- it performs *terribly* with big folders that have one or two changes) might be unusual.

I'm sure you can configure TM to skip files, but I'm really not in a position to provide Time Machine support. It's best to direct those kinds of things to Apple. :)

Brad 10-20-2008 02:31 PM

Dave, sounds like you're a dyed-in-the-wool FW man and that you haven't had a lot of either success or experience with eSATA to date. If you care to elaborate which (eSATA hasn't worked that well in your experience, or you just haven't used it much), that'd be nice. Especially given that we're likely going to be using eSATA a lot more in the future with FW going the way of the dodo bird.

I didn't think I'd get 3 Gbps, but I assume that setting it up that way would be 2x faster than whatever performance I got with 1.5Gbps... But are you saying that my back-of-envelope calculations of possibly 3-4x over FW800 are totally delusional and it probably wouldn't be that much faster (meaning it also wouldn't be 7-10x faster than USB 2?)

Trying to figure out how much I want the MBP w/expresscard & FW support... over the MB with only USB 2. I like the smaller form factor of the MB.

Anyone else: if you've played around with eSATA speeds when backing up using SD! and booting off eSATA (though I'm not as worried about booting support as I am about the speed diffs with FW800 &/or USB 2 when doing large/daily changing backups), please tell us your experiences, if you would!


dnanian 10-20-2008 02:47 PM

Assuming that FW is going away because it was removed from the MacBook is, I think, lacking any factual basis... and assuming it's going to be replaced by eSATA in any short term is similarly nothing more than a guess (and, in my opinion, a bad one).

I have not yet found an eSATA adapter for the MBP that will work at boot time. That doesn't mean there isn't one: I just haven't found one. In my opinion, no bootability = I won't use it. That said, you could use eSATA and then boot with FW if your drive supports both.

Note, too: some eSATA connections (e.g. the Seagate FreeAgent drives) have problems in some configuration, and can have block errors. My apologies for the vague reference, but I can't find the eSATA interface manufacturer reference that originally talked about this (specifically, certain Oxford eSATA bridge boards cause errors).

Finally, I don't think you'll find that you're saturating your FW bandwidth with a typical copy. Usually, you'll only get 'turbo' performance when you're streaming a single, huge file with optimal block sizes and a blank, optimized destination. I don't think you're going to get nearly what your b-o-e calcs show, except in totally optimal conditions... and a backup is not one of those.

Brad 10-20-2008 02:57 PM

Ah..., I see how you carefully didn't come out & call me delusional--thanks! :D

I think what you're saying is that a USB 2 connection will definitely be slower, but not nearly as slow as I might think for backups, over a FW800 or eSATA based drive and if I really *really* like the smaller form factor, perhaps I should just get the late 2008 MB. (Esp given I'm not a gamer.)

Thanks--and if anyone else begs to differ--let's hear it! :-)

dnanian 10-20-2008 02:58 PM

Well, no. A USB2 connection is going to be significantly slower than Firewire. But eSATA isn't going to be significantly faster than FW800 for this purpose.

dnanian 10-20-2008 05:06 PM

Here's a reference showing bad behavior with eSATA from Sonnet (see the fine print at the bottom):

Brad 10-20-2008 06:55 PM


Originally Posted by dnanian (Post 22046)
Well, no. A USB2 connection is going to be significantly slower than Firewire. But eSATA isn't going to be significantly faster than FW800 for this purpose.

Ah. Okay, so if I buy the MBP, don't bother with the eSATA card, not worth the trouble, just use FW800 instead for backups.

And get used to lugging around the extra pound so my backups are faster or else put up with significantly slower backups using only USB 2 w/the MB (2-3x slower than FW800?). I may still do the latter just to save my back--which leads me back to really wishing the MB Air (I just can't bring myself to call it an MBA) could be fitted with 4 GB of RAM.

Thanks Dave (and for the reference link too).

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