mfcmfc
Contributor
Contributor

Is exFAT a good choice for an external hard drive with a virtual disk

Is exFAT the best choice for an external hard drive containing a VMWare virtual disk that I want to connect to both a Mac laptop and a PC desktop? The other choices are NTFS and HFS+, but both of these require 3rd party drivers and introduce a potential speed and/or cost penalty.

Mac 10.6 laptop running VMWare Fusion 4 and Windows 7 desktop running VMWare Workstation 8. The virtual disk contains 100 GB of SQL Server development databases. Copying these database to my laptop when I want to travel takes hours, even with an SSD, due to the Ethernet bottleneck, so I was thinking about using a portable hard drive that I could connect to either computer using eSATA.

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12 Replies
Shootist
Enthusiast
Enthusiast

I've had problems with USB thumb drives formatted exFAT in Mac OS X Lion when that thumb drive is moved to a Windows PC, XP or 7.

Windows report drive not ready, Needs to be formatted.

Have not had this problem with the same thumb drive formatted with same FS on a Windows 7 PC. Move it to Mac and Mac can read it, move it back to Windows and windows can read it.

If you are using this external drive only on a Mac then format it in the native Mac format, GUID Extended (Journaled).

If you are going to move it around I suggest either formatting it FAT32 on either Windows or Mac or exFAT on a Windows PC.

If you aren't going to be copying/saving files over 4GB in size (that is any one file 4GBs or more in size) to it then there is no reason to format it in exFAT.

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dlhotka
Champion
Champion

Nope, use FAT32, and choose the 'split into 2GB file' option when creating the VM.

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mfcmfc
Contributor
Contributor

I was thinking that exFAT was an improvement over FAT32. Why would FAT32 be better?

I currenly split the virtual disk into 2gb files.

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Shootist
Enthusiast
Enthusiast

exFAT allows files over 4GB to be stored on the drive. FAT32 only allows files smaller then 4GB.

Becasue every OS that I know of reads FAT32 volumes. Not all can read or write to exFAT volumes.

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mfcmfc
Contributor
Contributor

I'll only be using the VM on Windows 7 and Mac OS 10.6+, and both support exFAT natively.

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Shootist
Enthusiast
Enthusiast

OK but please check that the drive you format exFAT can be read on both systems.

Like I said in a earlier post I had a problem reading exFAT drive on Windows 7 that were formatted on Lion.

So if you are going to format that drive in Lion to exFAT make sure Win 7 can read it before you start copying/placing files on it.

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treee
Enthusiast
Enthusiast

That same problem you have with exFAT is also a known problem with FAT32 so the FAT32 suggestion is as "bad" as the exFAT suggestion.

I've created several exFAT volumes on usb thumbdrives as well as external drives to test how it went. Haven't seen any problems so I've now completely switched to using exFAT on thumb drives and external drives. I think this is the best suggestion one could do: test it for a bit, then choose if you keep it or use something else. Alternatively you could use some software that enables Windows to read and write HFS+ volumes or let OS X read/write NTFS volumes.

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WoodyZ
Immortal
Immortal

One thing I do not like about exFAT is it only uses one copy of the file allocation table (FAT) where FAT32 uses two copies, one at each end of the disk, so if something happens to the primary FAT the secondary FAT can be use to help recover but if something messes with the FAT on an exFAT disk you're screwed.

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dlhotka
Champion
Champion

I'm seeing some reports on my internal forum that exFAT may have lower performance on Mac's than FAT32 - early days, but unless you really do need >4GB, there's not much reason to not use FAT32.

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WoodyZ
Immortal
Immortal

dlhotka wrote: but unless you really do need >4GB, there's not much reason to not use FAT32.

I totally agree and even so I'd still prefer using NTFS and HFS+ with appropriate third party drivers to read/write to the other before I'd use exFAT until Microsoft adds additional FAT to aid in recovery.

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treee
Enthusiast
Enthusiast

You could try to recover the filesystem stuff, you could also restore a backup. I think the latter is the easiest and fastest solution but if it happens on the road away from your backup the first would be the easiest/fastest.  I'd be more worried about the performance aspect dlhotka points out.

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mfcmfc
Contributor
Contributor

Thanks for the advice. I guess exFAT is a bit too new to be trusted with important files.

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