anti eSata bias?

[bignose]

Hi. I'm planning on running 2 internal drives and then 2 eSata arrays. Some guys in #freenas gave fairly quick and unqualified remarks about "don't use that" or "I wouldn't use it" about eSata. Citing things like the cable getting wiggled and general unreliability. Random disconnections etc.

I'm curious if this is an opinion that is shared through the community or if this was just the opinions of a few random IRC folks. Thanks!

 

[jgreco]

Considering that your pool can be severely damaged by component loss, I rank it as reasonable and justifiable paranoia. eSATA is not the safest technology. You introduce cabling and separate power supplies into the mix. It is one of those things that you can do and it'll work just peachy up to that one day your brother's kid is over and in a fraction of a second he yanks a cord and suddenly you have lost an array's worth of disks. Also, eSATA implies port multipliers, known to be extra special gimpy hardware in many cases.

 

[bignose]

I thought zfs was fairly resilient? I'm not worried about my brothers kids, as my server is in a pretty isolated spot in my house but I would like to know more about port multipliers being gimpy..

 

[jgreco]

I thought zfs was fairly resilient?

Sure, but "resilient" does not mean "can safely experience catastrophic levels of drive loss and guarantee your survival.

I would like to know more about port multipliers being gimpy..

Try this.

 

[cyberjock]

I thought zfs was fairly resilient?

ZFS is resilient, as long as you don't do stupid things. Would you ever unplug an internal SATA drive with your server operating? That's exactly what you'd be doing if you bump the power supply or cable for an eSATA drive.

I'm not worried about my brothers kids, as my server is in a pretty isolated spot in my house but I would like to know more about port multipliers being gimpy.

And that is precisely why eSATA is a bad idea. After you've used it for a while you get complacent. You forget that you're 1 accidental bump from disaster. You're at work and someone bumps the desk your server is sitting on and *poof*, you have an unmountable zpool and you've just lost everything. This just happened to someone last week, and he doesn't even have external disks! So when you tell me its in an isolated spot and you're not worried I think to myself "Here's someone that hasn't figured out how risky it is... yet... but seems intent on finding out"

The same story for eSATA is true for USB, except USB is worse because often if you have even 1 bad sector the disk is dismounted. Really crappy when a single disk error causes the disk to drop from the array.

 

[jgreco]

The same story for eSATA is true for USB, except USB is worse because often if you have even 1 bad sector the disk is dismounted. Really crappy when a single disk error causes the disk to drop from the array.

Oh, let's not be giving SATA port multipliers a free pass there. This happens with (some?) SATA port multipliers too.

 

[cyberjock]

I will say that my SAS expander never had a problem. :)

 

[jgreco]

Yes, basically I'd expect an SAS expander to be enterprise quality gear, which doesn't necessarily mean problem-free. But most of them are LSI, even the one on Intel's RES2SV240, and when coupled with an LSI controller, the compatibility is excellent, the convenience is high, and the problems few if any.

Compare that to SATA port multipliers, where you can get generic ones from China for $30. Somebody damn well better accuse me of being a hardware snob for suggesting you look at the delicious build quality of that product.

 

[tingo]

Also, some esata boxes (enclosures) are junk, based on others experience (lots of gory details in various forums).

 

[jgreco]

That's what happens when you design something to be "just barely good enough". Basically they mix the generic SATA port multiplier I listed above with the shabbiest knuckle-slicer chassis design they can find and then sell it like it's the ultimate storage solution.

And I am so disappointed in all of you, no one accused me of being a hardware snob.

 

[cyberjock]

How about...


"You're a hardware snob.. but not because you looked at the delicious build quality of that low priced chinese product!"

Boom shaka-laka.