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#33869 - 04/17/15 12:23 AM Understanding Snowy/Yosemite
artie505 Online


Registered: 08/04/09
I'm running OS X 10.6.8 and 10.10.2 on my MBP, and I'm confused by the way they interact...or, more precisely, fail to interact.

I can see and interact with Snowy from Yosemite, but not vice versa.

In Snowy, Finder can't see the Yosemite partition at all, Disk Utility (1) sees it, but it's not recognized and is greyed out, and Terminal (2) also sees, but doesn't recognize, it; the only action DU will allow as respects the volume is "Erase". (Terminal (2) seems to be cool with my Recovery HD.)

In addition, DU > Get Info tells me that the volume is not bootable while System Preferences > Startup Disk shows it as bootable but identifies it as OS X 10.7, rather than 10.10.2. (1)

Will somebody please explain why my Yosemite partition is both invisible, semi-visible, and Lion all at the same time?

Thanks.
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#33873 - 04/17/15 09:25 AM Re: Understanding Snowy/Yosemite [Re: artie505]
freelance Offline


Registered: 08/05/09
Loc: London, UK
I do the same: main partition SL, up-to-date partition Yosemite. The first problem I experienced was that Carbon Copy Cloner would not copy Yosemite fonts when copying from SL. I asked the CCC developer about that and told me the differences between the two OS's:

Apple introduced some changes to HFS+ filesystem compression in Yosemite that are not backwards compatible. If you want to access any system files on a Yosemite volume, it must be done on a system running 10.9.5 or later. CCC 4 will warn you if you attempt to copy a 10.10 volume while booted from an OS older than 10.9.5, but CCC 3.5.7 was released before that information was available, so it can't give you the right advice on that scenario.

I don't know why this means you can see SL in Startup Disk when booted in Yosemite, but can't see Yosemite in Startup Disk when booted in SL.

I just hold the alt key when I want to move from SL to Yosemite.
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Mac Pro dual-2.4 GHz, 10.13.6, 24 Gb RAM, 250 Gb Samsung EVO SSD/Velocity Solo PCIe card, 2x3Tb Seagate HD, 1x3Tb Hitachi HD, Dell 2408WFP; Canon PIXMA iX6550; CanoScan 8800F; MacBook Air 1.8 Ghz, 8 Gb RAM, 10.14.1, 256 Gb SSD; BT Home Hub 6/Wi-Fi Extender.

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#33895 - 04/18/15 11:05 PM Re: Understanding Snowy/Yosemite [Re: freelance]
artie505 Online


Registered: 08/04/09
Thanks for your input.

Originally Posted By: freelance
The first problem I experienced was that Carbon Copy Cloner would not copy Yosemite fonts when copying from SL.

I'm still running CCC 3.5.7, and it doesn't even see my local Yosemite volume when I'm in Snowy...presumably because Finder can't see it? (I was, however, able to create an external, bootable Yosemite clone [from within Yosemite] with Terminal > ditto.)

Originally Posted By: freelance
I asked the CCC developer about that and told me the differences between the two OS's:

Apple introduced some changes to HFS+ filesystem compression in Yosemite that are not backwards compatible. If you want to access any system files on a Yosemite volume, it must be done on a system running 10.9.5 or later.(Emphasis added)

And, yet, while neither Snowy > Finder & CCC can see my local Yosemite volume, they can both see and access my external volume.

Originally Posted By: freelance
I don't know why this means you can't see SL in Startup Disk when booted in Yosemite, but can see Yosemite in Startup Disk when booted in SL.

You misread my post... I see all my volumes in Yosemite > Startup Disk; it's Snowy > SD that is ??? (I dunno what word to use.) It identifies my local Yosemite 10.10.2 volume as OS X 10.7, and it doesn't see my external volume at all (although an option boot does see it).

This "now you see it...now you don't" thing is extremely confusing!!! confused


Edited by artie505 (04/18/15 11:46 PM)
Edit Reason: Clarification
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The new Great Equalizer is the SEND button.

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#33897 - 04/19/15 12:44 AM Re: Understanding Snowy/Yosemite [Re: artie505]
freelance Offline


Registered: 08/05/09
Loc: London, UK
Oops! I should have said, "I don't know why Startup Disk can't see Yosemite when booted in SL, but can see SL when booted in Yosemite."

Mike Bombich warns not to use CCC 3.5.7 to make clones of Yosemite. I was trying to do that and noticed that 3.5.7 can not clone Yosemite system fonts. I was trying to add the new Yosemite fonts to my SL collection and returning errors. That's why I asked Bombich.

You should really buy CCC 4.0 for use with Yosemite.
_________________________
Mac Pro dual-2.4 GHz, 10.13.6, 24 Gb RAM, 250 Gb Samsung EVO SSD/Velocity Solo PCIe card, 2x3Tb Seagate HD, 1x3Tb Hitachi HD, Dell 2408WFP; Canon PIXMA iX6550; CanoScan 8800F; MacBook Air 1.8 Ghz, 8 Gb RAM, 10.14.1, 256 Gb SSD; BT Home Hub 6/Wi-Fi Extender.

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#33898 - 04/19/15 01:00 AM Re: Understanding Snowy/Yosemite [Re: freelance]
artie505 Online


Registered: 08/04/09
Originally Posted By: freelance
Oops! I should have said, "I don't know why Startup Disk can't see Yosemite when booted in SL, but can see SL when booted in Yosemite."

It looks like SD can see Yosemite in Snowy but can only identify it as something not specifically identifiable, but beyond OS X 10.6, ergo 10.7; restarting from SD > 10.7 does get me to Yosemite. Looking backwards, on the other hand, Yosemite knows what it's seeing.

Originally Posted By: freelance
Mike Bombich warns not to use CCC 3.5.7 to make clones of Yosemite. I was trying to do that and noticed that 3.5.7 can not clone Yosemite system fonts. I was trying to add the new Yosemite fonts to my SL collection and returning errors. That's why I asked Bombich.

As I said, CCC 3.5.7 in Snowy can't even see my Yosemite volume, let alone clone to/from it; your experience seems to differ from mine. (I'm going to e-mail Mike and ask him about our differing experiences.)

Originally Posted By: freelance
You should really buy CCC 4.0 for use with Yosemite.

Oh, I most certainly will...eventually. (I don't know why I'm putting it off for a lousy $20?)
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The new Great Equalizer is the SEND button.

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#33899 - 04/19/15 05:16 AM Re: Understanding Snowy/Yosemite [Re: artie505]
dkmarsh Offline

Moderator

Registered: 08/04/09

You've run into the notorious Yosemite Core Storage issue. Core Storage is an Apple technology, first appearing in Lion, that introduces a new "logical volume format" layer between the partition scheme and the HFS+ filesystem. Its purpose seems to be to allow multiple physical volumes act as a single logical volume, as in Fusion Drive, and to facilitate whole-disk encryption.

When Yosemite was introduced, there were numerous reports from those running Snow Leopard noting a variety of strange partition-related issues, of which yours is a prime example. (See for instance Yosemite: Questions; several posts, mostly in the middle third of the page, show folks grappling with such problems.)

I don't have time to research the subject for you, but you can start with John Siracusa's Lion review, wherein Core Storage is outlined in depth, as well as his Yosemite review covering the new 10.10-specific implementation. The latter might shed some light on the difference between your internal and external volumes.

It appears that reversion from Core Storage back to plain HFS+ is possible in some cases...maybe yours: OS X Yosemite, Core Storage, and partition woes.

Apple's documentation is characteristically minimal. The best (though terse) information I could find from the horse's mouth is in Yosemite's diskutil man pages. Scroll down—way,way down—to corestorage.
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#33901 - 04/20/15 02:03 AM Re: Understanding Snowy/Yosemite [Re: dkmarsh]
artie505 Online


Registered: 08/04/09
Originally Posted By: dkmarsh
(See for instance Yosemite: Questions; several posts, mostly in the middle third of the page, show folks grappling with such problems.)

So it doesn't get lost in the shuffle, I'll begin by pointing out that your link takes us directly to that third page.

Thanks for the reading list; although much of what I read was beyond me, I did get the point. (One curious thing I noticed is that there seem to be inconsistencies between various reports of Core Storage issues.)

Bottom line, though, is that after I finish one more tax return I'll most likely not see Yosemite again until next year's returns are due, so while I will bookmark your reversion link, I don't think I'll get involved with trying to implement its suggestions; it's simply not that important to me to be able to see Yosemite from Snowy.

Thanks again for shedding some light on a real puzzlement. (Since you didn't link to any other threads, may I assume that this is the first time the Core Storage issue has come up here? That, in and of itself, would be curious.)
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The new Great Equalizer is the SEND button.

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#33912 - 04/20/15 06:13 PM Re: Understanding Snowy/Yosemite [Re: freelance]
artie505 Online


Registered: 08/04/09
Here's what Mike Bombich, Carbon Copy Cloner's developer, has to say:

Quote:
Hi Artie,

Originally Posted By: artie
I'm still curious about my and freelance's different experiences with CS and its interaction with CCC, though.

The only thing I can say about that is that indeed, it's terribly inconsistent from one system to another -- some systems get a "bonus" forced CoreStorage modification while other systems do not. There has been a lot of chatter on various developer forums about this, and some people think they've cracked the secret (e.g. it depends on whether the Mac's Intel processor has AES-NI support, though the debate seems to still be open). That, of course, is the problem -- Apple doesn't document this modification. There's no warning given prior to installation, nor is there any explanation given afterwards nor in Apple's Kbase. As long as you behave as Apple expects you to -- never look back, never run an older system, always upgrade, upgrade UPGRADE!, you shouldn't have to be bothered with technical details like this.

Mike


Edited by artie505 (04/21/15 12:10 AM)
Edit Reason: Quantify Mike
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Moderator:  alternaut, dkmarsh, joemikeb