A hard-to-beat combination....

[msloane]

...or at least I think it could be.

Having *pretty much* settled on the QNAP TS-109 Pro II for my NAS, the only question that remains is how to handle NAS backups to an external (eSATA, USB, etc.) drive.

Then I found this....

http://www.thermaltakeusa.com/Product.aspx?C=1346&ID=1731

Connect this baby via eSATA, pop in a drive, and I can have as many off-site drive backups as drives I buy. Pop in a drive, backup happens, take the drive off-site, pop in another.

There's also this one....

http://www.newertech.com/products/voyager.php

...but the Thermaltake costs less than half as much, and I don't really need the Firewire connectivity.

Anyone have any experience with either of these?

 

[msloane]

Bump, and....

Cheesy, I know, but I'm bumping my own message, because I've continued my due-diligence in the month since I started this thread, and still haven't pulled the trigger on my purchase.

Here's the sticking point -- my intent (see original message) is to go with a single-drive NAS (QNAP TS-109 Pro II) that I will periodically back up (via eSATA) to external drives that I can rotate off-site.

But the more I read and research, the more horror-stories I glean from people who report PAINFULLY SLOW backup speeds doing precisely what I propose to do, namely backup a NAS drive to an external drive via eSATA.

I'm leaning toward a 1.5TB drive (the Seagate ST31500341AS). Very quickly, that drive will be populated to nearly 800 gigs.

And from everything I've read, it sounds like it could take (depending on the horror story) anything from a day to a week to back it up.

Is there anyone out there who is currently doing what I propose to do, and would care to share information with me? Are your experiences different from what I've been reading?

Or am I setting myself up for a potentially unworkable, frustrating, and expensive disappointment?

Many thanks, and your thoughts are appreciated....

--Michael

 

[thiggins]

Can you point me to some of what you've read that provides specifics on eSATA backup speed.

Dennis Wood has measured around 33 MB/s doing eSATA backup on a QNAP TS 509 Pro

 

[msloane]

Okay....

Thanks, Tim.

If I'm reading that right (and if I'm not, then it may be the root of my concern and confusion), 33 MB/s (megabits per second) very roughly translates to 4.7 megabytes per second...which is roughly 282 megabytes per hour, which (by my admittedly questionable math) sounds like a little over a gigabyte every four hours.

At that rate, backing up 800 gigs will take....well, what would seem like forever, I'm sure.

However, if that's 33 megabytes per second, then we're in a much more reasonable range -- backing up 800 gigs at that speed would take about seven hours.

Its possible I'm just over-analyzing this...if that's the case, and backing up 800 gigs from a TS-109 Pro II via eSATA can be accomplished within a reasonable timeframe (overnight, let's say), then someone please put me out of my misery....

Thanks....

P.S. I find SmallNetBuilder to be incredibly informative, and I appreciate all the help as I continue to learn....

 

[thiggins]

Big B is Bytes. Small B is bits.
MB/s is MegaBytes per second.
Mb/s is Megabits per second.

On SmallnetBuilder, we tend to use Mbps for Megabits per second to avoid confusion.
I should probably write it out, since I notice that some forum posters don't follow this convention and require follow-up posts for clarification.

Glad you enjoy the site. Please spread the word!

 

[msloane]

Aha....

Thanks for clearing that up, Tim.

It's also possible that the crazy-slow eSATA backup speeds I mentioned were not from direct-connected devices...in other words, both the NAS and the eSATA were attached to a connected PC...meaning that network speed came into play.

In my case, the eSATA drive would connect directly to the NAS, so network speed won't be an issue -- and the copy command would be executed within the NAS itself, so it should hum right along.

That just leaves the NAS filesystem and internals (processor speed, memory, etc.) as the only variables....

...and in the case of the TS-109 Pro II vs. the TS-509 Pro that Dennis Wood was writing about, those differences are not insignificant:

500 MHz Marvell vs. 1.6 GHz Celeron
256 MB DDRII vs. 1 GB DDRII memory

So the question is, given these differences, how realistic is an eSATA speed approaching 33 MB/s from a TS-109 Pro II?

 

[thiggins]

This ExtremeTech 2007 roundup of 5 eSATA drives showed average read/write speeds ranging from 38 MBytes/sec to 72 MBytes/sec (scroll down to last graph). The test computer had an Intel Core 2 Extreme X6800 CPU, 2GB of RAM running XP. The eSATA port was on the motherboard via the Intel 975 chipset. So let's call that best case.

The Marvell Orion is a relatively low-powered storage System on a Chip (SoC), which typically has NAS transfer rates in the low to mid teen MB/s.
So my best guess is the teens are the best that Orion based NASes will do, and perhaps lower.

 

[msloane]

NAS Transfer Rate vs. Read/Write speed

Tim....

Unless I'm missing something here (which is entirely possible), I'm not seeing the correlation between NAS transfer rates (which in the context of the conversation, I presume you mean to be a measurement of the speed of data movement from the NAS to an attached eSATA drive) and the read/write speeds of the drives themselves.

Nevertheless, the key piece of information I'm trying to boil all this down to is this: Roughly speaking, how long would it take to backup (let's say) 1TB of data (500K to 10MB file sizes, mostly photos and MP3s) from the TS-109 Pro II to an attached eSATA drive.

In my case, the hard drives in both the TS-109 and the eSATA would be 1.5TB Seagate ST31500341AS, and the eSATA "enclosure" (not really an enclosure, per se) is the Thermaltake BlacX.

Around 8 hours to run the backup? Works for me.

Much more than 10 hours? Gonna be a problem.

The trick for me is to figure out how to use the available data to come up with the answer I need.

Any pointers appreciated....

 

[thiggins]

What I was trying to say is that best case, i.e. if the NAS can read and write at the speeds supported by the eSATA drives I mentioned, you're going to get between (rounding) 40 to 70 MB/s.

So, taking the highest number, 70 MB/s is 4.2 GB/min and 252 GB/hour. You can do the rest of the math.

The question is whether an SoC-based NAS can support those rates to eSATA. I'm guessing no. But does anyone have data?

 

[msloane]

Gotcha....

Here's the transfer rate specification on the Thermaltake "toaster enclosure" I'm looking at:

"Supports eSATA Transfer Speed up to 3Gbps"

So, as you point out, the possible choke point would be if the SoC architecture of the QNAP TS-109 Pro II itself can sustain that type of transfer rate.

The question is, how do you derive the data to settle the issue from the 109's specifications?

 

[thiggins]

First, the 3 Gbps spec is useless. It is the maximum PHY data rate and only remotely related to actual delivered throughput.

You can't derive the performance data. You can only measure it.

 

[msloane]

Okay...thanks, Tim.

So, to finally put this badly-beaten horse in its grave, let me ask one last question....

Given what is known about the Seagate ST31500341AS, the Thermaltake BlacX, and the Qnap TS-109 Pro II, does anyone think that these devices, acting in concert, would provide eSATA backup performance roughly in line with my expectations (e.g., backing up +/- 1TB in +/- 8 hours)? Or will I only know after I get everything, put it together, and test it in situ to find out?

Please understand...I'm not looking for exact numbers, nor am I looking for anyone to blame in case things don't work out as I expected them to.

I'm simply looking for an anecdotal guesstimate, something along the lines of....

..."sure, that'll work, I do it all the time."

or

..."are you kidding? It'll take 15 hours (or more) to backup a terabyte that way!"

I can only imagine that there are at least some people who currently do what I propose to do, namely backup their NAS to an external drive....

...and if they're anywhere, they're on SmallNetBuilder!

 

[msloane]

From another thread....

The thread "Your thoughts about QNAP TS-109 II," started by a member named "Cino," just received a reply to a posting I made, concerning the backup issue we're discussing here.

It's from a member named "Osamede," and here's the post.

Tim, after I mentioned that I had read some horror stories concerning backup speed...and you asked for some specific examples...it turns out that there are TONS of anecdotal horror stories in QNAP's forums.

(I knew I had seen them somewhere...just couldn't recall where....)

I made email contact with someone named Albert Lin at QNAP, presumably in pre-sales support. I asked him straight out if I will be able to do what I need to do...haven't received an answer yet, but I'll post here when I do.

But all this creates a new question:

Is there any single-disk NAS that has a robust (e.g. fast) backup system/method to an externally-connected disk?

Thanks....

 

[thiggins]

"Robust" and fast are two different things. I'll assume you want both.

QNAP (and every other Taiwan and Chinese company) are on Chinese New Year break this week. I will ask them about this when they return.

I don't test external backup, so can't comment.

I did find this post, which seems to offer an explanation and states why the problem isn't exclusive to QNAP.

 

[msloane]

Well, okay....

Okay...I meant fast, hoping that robust would be somewhere nearby.

In the interest of full disclosure, I know nothing about Linux (other than how to spell it). So 'rsync' and 'cp' go right over my head...presumably, a function in the NAS's interface executes those commands under the covers.

That said, I have to wonder if the limitations on throughput they're talking about on the QNAP forum -- which relate to USB -- would also relate to eSATA?

Thanks....