External USB HD slows boot.

[sibrow]

First post, sorry if it's too long or something. New Mac user but reasonably computer proficient.

Setup: iMac 2008. FW & USB Seagate FreeAgent Desk for Mac - Used for Time Machine.

Problem 1: Drive plugged in via FW800. When Mac is turned on the drive doesn't mount. To get it to mount I can either unplug and plug again, or put mac to sleep then wake again. Couldn't find a solution after ages Googling. Best I got was 'new macs have inferior FW chip to previous broadcom chip, live with it'. Not sure if that can really be the source of that problem though. But I got fed up and switched to using USB.

Problem 2: Using USB the drive mounts fine on start, but startup times are much longer. With drive dissconected startup from push button to dock is 50secs. With drive plugged in time can be up to 3mins. That is ridiculous. I have Googled for ages and found few people with my problem. All threads I found just faded out with no resolution. The problem is independant of Mac or HD make.

Once the drive went into a cycle of unmount, mount repeatedly. I left it for a bit and it seemed to fix itself. Sometimes backups fail, but then I manually do 'Back up now' and it is fine.

Tried disk utility repair, but says drive is fine. Tried setting boot disk to Mac HD again, but that didn't help. Not sure where to go from here. Is the drive deffective? Or the iMac? Are FW mounting problems common? Are USB long boots common? Any help welcome, even just "my setup works fine using FW".

Thanks, Simon.

 

[Makosuke]

I'm much more inclined to blame the drive rather than the Mac, particularly since both the USB and FW interface are giving you problems.

I, for example, have a brand new Mini with both a FW800 and USB drive plugged into it (OWC and Fantom brand, respectively), and it reliably boots and mounts everything. Boots also take no longer than you'd expect. Same goes with other, older Macs and both FW400 and USB2 drives on other systems I've worked with.

What it sounds like is happening is the Seagate is taking too long to initialize or something of that sort; when attached to FW800, the Mac eventually gives up and ignores it (hence no mount), while it keeps waiting for a long time on USB2, until it eventually comes online.

Could be that the case auto-sleeps when the computer connection appears to it to be dead, which it would when the Mac is off, but then when you turn on the computer the drive either doesn't reliably detect that condition, or does so with timing that the Mac "misses", and so ends up not mounting it or waiting a long time for it.

The fact that you're also getting Time Machine errors periodically makes me even more suspicious that the drive is flaking out periodically.

I have no idea if the drive itself is just bad, or if there's a problem with Seagate's controller as far as compatibility goes. I will note that I've read of a lot of problems with Seagate's external drives, and this was before the recent Seagate firmware bricking debacle. Not saying that's definitely the case, just that I wouldn't be too surprised if that turns out to be the cause.

You could always try Seagate tech support and see what they tell you.

 

[patrick0brien]

-sibrow

Above all, please realize that even at full 800mbs FW800 speeds, or 480mbs USB (theoretical max) speeds, is still way slower than the 3gbs your Sata internal drive will feed your system. This is will increase your boot time from 3.75 to 6.25 times what you are used to.

 

[sibrow]

Thanks. USB dodgy in general?

Above all, please realize that even at full 800mbs FW800 speeds, or 480mbs USB (theoretical max) speeds, is still way slower than the 3gbs your Sata internal drive will feed your system. This is will increase your boot time from 3.75 to 6.25 times what you are used to.

- I realize that, but I'm not booting from the external, only using it for periodical backups. So this shouldn't increase boot time?

I'm much more inclined to blame the drive rather than the Mac

-Thanks, that's what I was hoping for. I didn't know there were problems with Seagates as they are the largest manufacturer and I couldn't find any bad reviews. Perhaps because their externals are not so popular. I was hoping maybe there was some kind of software fix, but I will do as you suggested and contact tech support. Looks like a refund and a MyBook is in order. Thanks for your input on your systems, that was helpful. And This does seem to be the logical explanation. The disk spins up, Mac does nothing, disk spins down, mac nothing, disk spins up, mac loads.

Also, I would like to know how reliable other USB peripherals are for people. I find certain combinations of hubs and devices can cause devices to disconect. And I think one of my hubs died so I swapped it out after it stopped working. I do remember Windows used to mess up USB on occasion, but then they would auto reconnect, giving you those annoying balloon helps for each device on the hub. Is USB just a bit picky, or have I been unlucky, perhaps I use too many devices?

Thanks guys for the help

 

[Makosuke]

Some USB setups can be finicky, but I've certainly seen systems with a half-dozen peripherals connected through a hub without issue. I'd say maybe the hub is to blame, based on one particular Belkin hub I had that was incredibly flaky. Alternately it could be a particular device, but the only way I can think of to test that for sure is to remove one at a time and see when the problem goes away.

Purely anecdotal, but for example the aforementioned backup drive is connected via USB2 to a mini server 24x7 and has never had a problem. A (bargain basement) USB2-based blu-ray drive, on the other hand, is incredibly flakey, whether externally or bus powered--some times I'll need to reconnect it three times just to get it to work properly, MacOS or Windows.

Oh, and incidentally, the big problem with Seagate's externals (desktop, not portable) was the first generation when they had MAJOR overheating problems that was killing an abnormally high number of drives. Ironically they were so cheap at the time a lot of people were buying them then just gutting them for the drive, since it was cheaper than buying a bare one and the cooling wasn't an issue that way.

Good luck with a MyBook; I had one for a while that seemed to work just fine, though it was just an emergency interim drive.

 

[sibrow]

Thank, solved.

I was all ready to return the drive for repair so I had it unplugged. But then I noticed that oddly boot times were now long, even without the drive plugged in.

So a bit more testing later and unplugging of other peripherals I decided to try zapping the PRAM. I hadn't done that before, but I should have done it sooner becuse it fixed all my problems. Now the drive mounts fine over fire wire, boot times are fast, and so far everything is reliable.

So thanks for the advice, and over all it seemed to be a very strange problem. Thats another fix it technique to add to my vocabulary.

 

[itickings]

Above all, please realize that even at full 800mbs FW800 speeds, or 480mbs USB (theoretical max) speeds, is still way slower than the 3gbs your Sata internal drive will feed your system.

Sure.

This is will increase your boot time from 3.75 to 6.25 times what you are used to.

Now that on the other hand looks plain wrong. Did you just divide theoretical bits with different meaning here and there to get boot time differences?

Unless you have an internal drive that can push 300MB/s, it doesn't mean squat that the interface can do that. Aside from that, you have to factor in latency issues, how much of the boot process that is I/O bound, etc, etc...

All in all, I agree that USB2 is really not suitable for booting from, and that a hard drive on FW800 will realistically be slower than a modern internal drive. If one's going to present numbers on this matter however, they should come from real life experiences, and not pulled out of thin air. People may actually believe numbers they read.

(And of course, my apologies in advance if the numbers were indeed scientifically produced, and just happened to match 3000/800=3.75 as well as 3000/480=6.25 )