Reinstalling Snow Leopard without loosing ones Apps, Photos and such?

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Level 1

2 points

Reinstalling Snow Leopard without loosing ones Apps, Photos and such?

Hi,
someone I think on these forums in fact advised me recently to do a reinstall of Snow Leopard as the only way of fixing some very very odd system behaviour (file system regularly freezing up).

It was said that installing OVER my current running copy of SL would leave all files except those system ones intact and no data loss would incur.

Basically I do not have enough room to back all my data up on external drives and would like to know if this is in fact true, that even system folders (content in for example "Sites" or "Pictures" or "Music" remains untouched?

Will App preference files also be left alone or will I need to reinstall my Apps after this install?

Thanks for your help in advance,
just a little nervous about all this.

PS: Snow Leopard, on a 128GB M225 Crucial SSD in a MacPro3,1.

Mac Pro (early 2008), Mac OS X (10.6.1), Dual Quad 2,8Ghz / GeForce 8800GT / 16GB RAM / Boot: 128GB Crucial SSD

Posted on Mar 21, 2010 11:23 AM

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Answer 1

baltwo

Level 9

62,362 points

Mar 21, 2010 11:44 AM in response to meemorize

It's true. Best, however, is to get a 1 TB ext HD (they're under $100 USD) and back stuff up.

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Answer 2

R C-R

Level 6

17,782 points

Mar 21, 2010 12:27 PM in response to meemorize

Basically I do not have enough room to back all my data up on external drives …

As a very wise engineer (who has among other things worked on HD drivers for Apple) once advised me, you don't own any data unless it exists somewhere other than on a single hard drive. It is a derivate of an old industry saying: There are two kinds of users, those that have lost data & those that will. Both basically say the same thing: if you don't back up your data, sooner or later you will regret that decision.

As others have said, reinstalling Snow Leopard will not erase your data … unless something unforeseen goes wrong during the process. That is extremely unlikely -- but it is not impossible. That is something you should be nervous about & the only solution is to back up at least all the data you cannot afford to lose. If nothing else fits your budget, get enough DVD's to do the job. It is the cheapest insurance you will ever get.

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Answer 3

meemorize Author

Level 1

2 points

Mar 21, 2010 11:14 PM in response to meemorize

Thank you both for your comments.

I should have been more clear about my setup, all my files are on 3 'secondary' drives in my Mac Pro, the SSD hold merely the filesystem and apps.
All data is on the other internal drives, linked to the orignal /user/'folder'/ by symbolic links.

So even if the boot drive fails after installing it I still have all data on accessible other drives.

One more question before I begin the install, what is such 'overwrite' (non formatting) install called?

I just want to make sure that when I do it all I do not accidentally wipe everything.

Do I boot off of the SL DVD then install or do I start the install by inserting the DVD while running SL and clicking on the installer?

Thanks again you two,
really appreciate your clarifications.

J.

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Answer 4

baltwo

Level 9

62,362 points

Mar 21, 2010 11:42 PM in response to meemorize

There is only one install option. Everything except the OS stuff is left in place, as long as you don't erase the boot volume before installing. You can start the installation either way. Starting from the current OS requires entering your username and password; whereas, booting from the install disc doesn't.

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Answer 5

R C-R

Level 6

17,782 points

Mar 22, 2010 3:27 AM in response to meemorize

Do I boot off of the SL DVD then install or do I start the install by inserting the DVD while running SL and clicking on the installer?

I suggest clicking on the installer. There is at least one non-obvious difference between the two methods (from what I have gleaned by comparing the installer logs for the two): when you start this way & your system is connected to the Internet, the "Install Mac OS X" application queries an online Apple database of applications incompatible with Snow Leopard, adding any it finds to the very short list already on the DVD. This list is then written to a temp file on the HD & used after the automatic reboot off the DVD to determine what if anything to move to the "Incompatible Software" folder.

From what I can tell, the database has been updated at least once since the DVD was mastered & I assume Apple will continue to update it as more incompatible apps are discovered. Thus, starting from the "Install Mac OS X" application insures that the installer has the latest list.

This does not happen if you initially boot off the DVD, I suppose because its version of Snow Leopard has no network settings & thus doesn't know how to connect to the Internet.

There may be other subtle differences like this, although I'm not aware of any as yet.

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Answer 6

meemorize Author

Level 1

2 points

Mar 22, 2010 3:44 AM in response to meemorize

Hello again,
I did intact insert the DVD into my running mac pro and clicked the installer which like you said prompted for my admin password as well as queried apples server.

Everything with the install itself went flawlessly and I haven't lost any files either.

However this did not at all fix my issues 😟

I am completely out of ideas on this since I cannot even pinpoint the error, it's like the entire read/write activities are halted.
I can still move already opened windows around, but anything els,. Literally, freezes for up to a minute, firefox, the dock, the menubar, mail...

Any ideas what this could be?
Memory check didn't find anything wrong with the 16GB of ram, so I'm inclined to blame it on the crucial 128gb m225 SSD I have running as my bootdrive.

Anyway, thanks again for the help.

J

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Answer 7

R C-R

Level 6

17,782 points

Mar 22, 2010 4:13 AM in response to meemorize

It is hard to say what the cause of the slowdowns are without more info from you, but I suspect it might have to do with how you have linked data on the other internal drives to the startup drive's /Users/ folder with symbolic links. Can you describe this in more detail?

You mentioned that the SSD holds just the filesystem and apps, so can we assume that is the startup drive & actually holds the root level System, Library, Users, & Applications folders … plus the several normally invisible root level files & folders (bin, sbin, & private folders; links to etc., var, tmp; the Spotlight-V100 file; & so on)?

Do you have symbolic links to each user account in a normal /Users/ folder (including /Users/Shared/), links to various folders in each account's normal home folder, or what? IOW, how is this structured?

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Answer 8

meemorize Author

Level 1

2 points

Mar 22, 2010 4:37 AM in response to R C-R

I will gladly give out any info you need, to be honest the only next step I can think of is starting to replace the SSD with a new one, so anything I can do to avoid this..

Above is an image of my user folder,
Basically all 'aliases' are symbolic links that I have created using the Terminal command (ln -s /Volumes/"diskname"/Documents ~/Documents, for example)

All the aliases point to the Volume "Storage" which is a new-ish (less than 6 months) Seagate Barracuda 1.5GB 7200rpm HDD.

Yes, you are correct this Boot Drive is the SSD (my apologies for misusing filesystem, by which I meant all mac os x installation created files).

So basically 'all' I did do that different to just a standard install of Mac Os X is that once installed I created these symbolic links so that the data could reside on external drives as opposed to heaping up on the rather small 128GB SSD.

There is only 1 user, myself, admin. Guest account has been disabled. Auto login is switched on, no password entered to start os x.

User, Library, App support, Apps and those invisible folders are on the boot drive (SSD) and have not been moved.

So as opposed to linking my entire /user/folder/ to an external volume I only picked a few data heavy ones (Documents, Pictures, Downloads, Movies, Music, Sites).

Due to me being in New Zealand I won't be able to reply until the morning, but rest assured I honestly cannot express how happy I am about you taking an interest in this issue, it's been plaguing my Mac Pro 3,1 for some time now and I have resorted all options I could think off.

So thanks again.

Jannis

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Answer 9

The hatter

Level 9

60,990 points

Mar 22, 2010 4:56 AM in response to meemorize

There is more to know and take into account when using SSD.

It is rather easy and trivial on Mac Pro to have the default /Users but still have the entire personal user home folder located on 2nd drive and later just use ACCOUNTS control panel to direct the system (after installed what you need) rather than use symbolic links and such.

And a lot cleaner in the end.

Until Apple adds TRIM support, you have to take care of that on your own.

http://forums.macrumors.com/showthread.php?&t=841803

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Answer 10

R C-R

Level 6

17,782 points

Mar 22, 2010 5:39 AM in response to meemorize

First, I would like to thank you for what is probably the clearest & most comprehensive reply to a request for more details I've ever seen in these forums. Second, I must inform you that I have no direct experience with setting up a system this way, so I probably can't help you anywhere near as much as some other user with more experience -- whom I hope will chime in soon.

Anyway, from what little I do know about this, I don't see any obvious problems with how you have set this up. The only thing that occurs to me at this point is something you have probably already checked, that being if Disk Utility's Verify Disk finds any problems with the file system structure of either the SSD or the Seagate Barracuda. You might also check the permissions on the linked folders to see if that turns up anything odd, but of course this would have to be done manually since Disk Utility's permissions check won't do anything for them.

Also, I assume you have checked that all links on the SSD remain unaltered after reinstalling Snow Leopard & that double-clicking on any of them in Finder opens the expected folder on the Seagate … with or without the slowdowns?

Something else to try is using Onyx or a similar utility to clean user caches & perhaps system ones if the first has no effect.

BTW, I assume the 1.5 GB size is a typo, right?

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Answer 11

meemorize Author

Level 1

2 points

Mar 22, 2010 11:21 AM in response to meemorize

Hello again,

@The hatter:
Could you perhaps elaborate on the whole /users folder setup you are mentioning? I am a little lost as to where those settings are that I could later use in my Accounts panel that would replace Sym Links.

Also, ideally I will leave all my applications on the SSD for the faster startup time of course.

Also, how can I 'manually' TRIM my drive? I checked the link you attached but am unsure as to how this would relate my issue since they are just generally complaining about SSDs not working right, mine used to work fine for months and now acts up.

@R C-R:
Thanks. I tried to give as much info as I could comprehend myself, hoping I would not miss an integral part.

I have run Disk Verify and Disk Repair multiple time over the past couple of weeks, including just 2 days ago, and everything came up fine there.
Also I reset my RAM (CMD OPT+RP on startup), but this didn't help either.

I went through the folder like you suggested but there was no delay or hang up doing so and all links were directing me to the right folders.
When I say 'no delay' I mean that not just the file tree was displayed but also the video thumbnails for files were accessible immediately.

I have used Onyx before when I wasn't using a SSD but other people have told me that there is no point in defragging a SSD since it is designed to be randomly allocated bytes so even when defragging it would just remap the data randomly.

I have Onyx still on my system so if there is something specific you suggest I run, please let me know.
As for other software: I own a license for Drive Genius 2 also, if this are better/more suitable.

Last but not least: Yes, silly me, 1.5GB should of course be 1.5TB. Apologies.

Also, just for being completely transparent with my system:
- Mac Pro 3,1 (e 2008)
- 16GB RAM (8x2GB matched pairs)
- nVidia GF 8800GT 512MB
- 4 internal drives:
1) 128GB M225 Crucial SSD (boot)
2) Seagate Barracuda 7200.13 1.5TB
3) Seagate Barracuda 7200.13 1.5TB
4) Seagate Barracuda 7200.11 1TB (only used for Windows boot camp, entire drive)
- 2 internal DVD drives
1) Factory Matshita (seemed broken, reads fine does no longer burn DVDs)
2) NEC 3540a as a secondary (works perfectly)

Snow Leopard on this SSD was a clean install initially.

Thanks for your continued interest to all of you, really appreciate you sticking with this thread.

Many thanks,
J.

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Answer 12

The hatter

Level 9

60,990 points

Mar 22, 2010 12:55 PM in response to meemorize

Do more research - and consider picking up a copy of Pogue's "Mac OS X: The Missing Manual." Look at Accounts control panel?

Then read through the threads on TRIM on MacRumors and the long threads on Mac Pro Apple Discussion on TRIM, as well as Wikipedia.
http://en.wikipedia.org/wiki/TRIM

To my knowledge, and I am no fan of Seagate's non-SAS/SCSI drives, is there is no 7200.13 (maybe in some lab there are samples and prototypes).

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Answer 13

meemorize Author

Level 1

2 points

Mar 22, 2010 1:02 PM in response to The hatter

I will look at those options absolutely.
By Account control panel are you referring to "System Prefs" > "Accounts" ?

About the drive model, it may be a 7200.12? it's the latest rendition of their 1.5TB drive. My apologies.

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Answer 14

baltwo

Level 9

62,362 points

Mar 22, 2010 1:39 PM in response to meemorize

By Account control panel are you referring to "System Prefs" > "Accounts" ?

That's the Accounts prefPane. Open it, unlock the lock, CONTROL-click and hold on your account, select Advanced Options, and you'll see an option to choose the location for that account's home directory. To do this properly, i suggest moving everything back to your current home folder, deleting the symbolic links, wiping what's on the external, and copying your entire user folder back to the external. Then, you can do the change home directory location option. See http://www.macosxhints.com/article.php?story=20071025220746340 for more information.

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Answer 15

meemorize Author

Level 1

2 points

Mar 22, 2010 6:25 PM in response to baltwo

Wow, i never knew this existed.

Very cool. But I would ultimately like to keep the key files on the SSD, I mean why buy a fast SSD when I throw all things that need read/write access on another drive?

Or would you suggest moving the /user/ folder and then sym linking the Library and App folder back to the SSD?

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