Are eSATA drives hot swappable?

Question

I'm going to build a low power home server and I've been thinking about using some external eSATA enclosures so I can have external drives that I can add and remove from the server every now and then for backup purposes.

But I've never dealt with a eSATA drive before and I'm wondering how it works as far as plugging/unplugging goes... I've seen that eSATA drives are typically just plugged into a eSATA card that basically serves as a pass-thru to the SATA drives on your MB. So can one simply unplug and plugin a eSATA drive like they could a USB or Firewire drive? Or does the PC need to be shutdown first, just as if you were plugging/unplugging an internal SATA drive?

Answer 1

Your SATA controller (probably integrated in the motherboard) may or may not support this feature. It's likely if you're dealing with a new motherboard that it does. Basically, older motherboards supported something call IDE emulation rather than using native SATA Advanced Host Controller Interface (which does support hot-swapping).

From the Wikipedia article on SATA:

All SATA devices support hotplugging. However, proper hotplug support requires the device be running in its native command mode not via IDE emulation, which requires AHCI (Advanced Host Controller Interface). Some of the earliest SATA host adapters were not capable of this and furthermore some older operating systems, such as Windows XP, do not directly support AHCI.

...

While the drivers included with Windows XP do not support AHCI, AHCI has been implemented by proprietary device drivers.

Answer 2

I had this problem also with my bump down drives. (Buy a new one, clone the old one to it, replace the old one with the new, put old drive in external enclosure, reformat and new outboard drive created...)
I have been use Uwe Sieber's USB Drive Letter Manager and his Drive Tools for "Safe Removal", Eject, ReMount and others..
When I had a similar problem with my eSATA drives, I dropped him a line. Uwe recommended Hot Swap! by Kazuyuki Nakayama. It does the trick and more. My XP SP3 box redetects the Hot Swapped drive at device power up, although there is a "Scan for Hardware Changes" that is the first entry on the tray icon context menu, I don't generally have to use it.
Hot Swap! will dismount almost anything.

One thing Hot Swap! does not do, (or I haven't RTFM enough) is to turn off the light on a USB stick the way "Safely Remove Hardware" does, but I've looked at open handles, device manager, and "My Computer" and once Hot Swap! says it is gone, it is.

Answer 3

(re-edited from original statement presuming the difference was eSATA II versus SATA)

An example hot-swap statement from a SATA controller manufacturer, Addonics:

(1) Serial ATA hot swap feature works only with controllers basing on Silicon Image chip set from our inhouse testing. Other controllers that are not Silicon Image based may not support hot swap. You may consider adding one of the Addonics Serial ATA host controllers to your systems to ensure the hot swap capability. New controllers from Intel and other suppliers may finally support this feature. Please verify with your controller manufacturer if you need to have hot swap in your application. Hot swap is supported in Windows 2000 and XP only. On other OS, drive can be removed without crashing system. But replacing with a different drive can result in crashing the OS.

Answer 4

The SATA controller has to support Hot Swapping in order to be able to utilize it. I have seen motherboards that are 2-3 years old that support this, so it is not exactly based on age. From what I have read previously, if your SATA controller supports Hot Swapping, you will be able to eject the device like you do with USB drives. So pretty much if the device shows up in "Safely Remove Hardware and Eject Media", it is Hot Swappable.