So if you have a mac pro with limited internal storage and you want to build a few virtual machines with parallels
Is it possible to build them on external thunderbolt storage as to not take up space on the limited internal drives?
iMac
The Mac will boot from any directly-attached drive, Internal or External (but probably NOT an NAS drive.) You can Install Mac OS X on an External drive and then add Parallels or Boot Camp and another Operating system to it.
Isn't there a substantial reduction in system speed by doing this?
I thought the whole point was to keep the operating systems local?
Or is that no longer true?
thunderbolt 2 and a 7200 rpm drive are ok?
or do you need ssd external
Yes, a TB 2 SSD will be faster than a TB 2 7200 RPM drive but the HD will be satisfactory for most applications.
ThunderBolt or USB-3 or eSATA-II or III or Firewire-800 will all give you speeds that do not substantially limit the fastest data rate of a good 7200 RPM rotating hard drive. [which is a burst of data at about 125MBytes/sec, not sustainable.] That was the "standard" until recently.
The reason for walking away from SATA was that certain SSD drives can now go much faster, and SATA-III limits the maximum data rate possible. SATA-III is 6G bits/sec, or 750Mega Bytes/sec, now do-able (at this writing) mostly by fast Samsung SSDs. [SATA-II about 375 Mbytes/sec.]
There is no requirement to go faster, except your own expectations.
As users installing Mac OS X from a USB-stick can attest, it works from USB-2, but is slow.
Limited internal storage with VMs
