If you are truly talking a NAS here, it all depends on what performance you want out of a drive. I mention that because it depends on how you want the backups to be written on a given NAS grade disk. There are different types of NAS grade disks, which is explained here:
There's a performance penalty with some drives that you need to be aware of.
www.howtogeek.com
Disks aside, especially when it comes to Time Machine, let alone anything with a NAS:
Your write speeds will be limited to the slowest negotiated speed on your network. For example, if you have a switch or router that is 100Mbps or even 1Gbps, and the NIC in your NAS supports those speeds, you're great. However, if you are backing up your Mac via Time Machine to your NAS, and doing it over 802.11g WiFi, that connection is 54Mbps at the most, so your speed will be limited to the fastest that the Mac will use over WiFi. The second issue is that that speed will degrade the further you are away from the switch or router providing that WiFi speed, so your backups will take longer, and could affect the consistency of the writes of your backups, let alone writes to the NAS.
It is always best for that if you are hardwired (CAT 5/5e/6/6e/7) cable to your switch/router, and back up via that. That way, the speed of the writes will be limited to the speed of the switch/router. This is what I do, outside of connecting a simple USB SSD to my Mac and backing up my Mac to that disk via Time Machine. That actually may be more feasible and cheaper for you unless you already have a NAS set up.
I have both, so what I do is this:
- Back up my Mac to an external USB SSD via Time Machine.
- Back up my Mac to my NAS over Ethernet (CAT6).
- Back up my NAS to an external USB SSD, and store that backup offsite.
That way if I upgrade my Mac, I can blow away my Mac, use a USB installer to lay down the new OS, and restore my data via Setup Assistant, which will use Time Machine as its source for a restore.
If a disaster happens and I need to restore data, I can either pull it from my USB SSD or from the NAS. If the TM USB SSD is hosed, I go to the NAS. If both are hosed, I can restore my NAS from its external USB SSD, then restore the data from the NAS back to my Mac via Time Machine.
it's a 3-2-1 setup, so my backups are layered, and leaving my only single point of failure to be my house; hence why that NAS backup is stored offsite.
But for simpler setups, I'd be looking at a USB SSD first, then a NAS. But For either one, make sure that you have at least 1.5x the full size of the disk in your Mac so it cam accommodate everything you need for backups. If you Mac's SSD is 1TB, I'd be looking at 2-3TB, just to keep room for any additional versioning or data needed, so you won't lose data by having TM backups roll off to conserve space.
BL.
