Hard Drive Transfer Speeds

[jmanin]

Hello Everyone,

Being a noob and this is my first post, I'm not not sure if this is the correct topic forum to post this in. Please feel free to move it.

This is probably common knowledge here and I have known about it but tend to forget it until I saw it visually. I see people get hung up on performance numbers especially with hard drives. I just wanted to share with other newbies that hard drive transfer speeds do vary depending on where on the hard drive the read/write is taking place (outer track vs inner track). When comparing drive specs from manufacturers they may only list one number and that number is probably the highest transfer speed of the drive. But the drive can go slower. How much? I don't know. I just finished building two FreeNAS boxes and I am in the hard drive burn-in portion (patiently waiting...). Every now an then I would look at the SSH sessions and reporting graphs of the disk I/O just to check to see how things are going. It was then I saw how much of a difference in transfer speeds from the high to the low.

This chart shows one of my WD Red 4TB drives during the badblocks burn-in phase and you can see the transfer rate goes from a high of 158 MB/s to a low of 76 MB/s.

Side note: For those of you considering building your own FreeNAS don't forget to allow time for hard drive burn in. Each one of those alternating color "steps" represents nine hours of reading or writing to the disk.

 

[Ericloewe]

Side note: For those of you considering building your own FreeNAS don't forget to allow time for hard drive burn in. Each one of those alternating color "steps" represents nine hours of reading or writing to the disk.

9 hours? Lucky you, my 3TB Reds took some 7-8 hours for each badblocks step. Plus the read time. Times 4 passes. Times three runs (didn't have the rest of the server yet, so I had to do the burn-in on the old one).

Let this be a warning to others - you will be tempted to cut corners during burn-in and you must resist the temptation! :p

 

[CSP-on-FN]

[....]
Let this be a warning to others - you will be tempted to cut corners during burn-in and you must resist the temptation! :p

Ummmm! I know in general about burning-in hard drives, but after lurking here for a few weeks I've not yet seen any specific recommendations about doing it within FreeNAS. And 'burn-in' isn't mentioned at all in the current version of the docs ... so could you offer us a pointer or two please to any guidelines? Thanks.

(I'm a long-time fan of running SpinRite on my new drives, but Steve Gibson (SpinRite's author) hasn't got his "Large Format" capable version of SpinRite ready - yet, so I can't (sensibly) use it on my 4TB drives.)

Colin P.

 

[Ericloewe]

This is one option:

https://forums.freenas.org/index.php?threads/how-to-hard-drive-burn-in-testing.21451/

@jgreco also has a nifty script that automates the testing to a certain extent and includes performance data to help weed out bad drives, but I haven't seen it mentioned in a while.

 

[Ericloewe]

Note that badblocks also has trouble with large drives. Increasing the block size to 4k generally kludges around the problem and speeds up badblocks on AF drives.

 

[jgreco]

This is one option:

https://forums.freenas.org/index.php?threads/how-to-hard-drive-burn-in-testing.21451/

@jgreco also has a nifty script that automates the testing to a certain extent and includes performance data to help weed out bad drives, but I haven't seen it mentioned in a while.

I'll be getting back to that topic soon.

 

[CSP-on-FN]

Many thanks Eric and jgreco.
I've put a 'Watch' on that deliciously long thread and I'll spend a while reading it very soon.

Steve Gibson hints that his next version of SpinRite should get through a "meaningful" scan on a 2TB drive "overnight".

(Just for the record - I've got no connections with Steve Gibson or with GRC.com so I hope I don't appear to be plugging his products in my first posts here!! It's just that I've listened to his weekly Security Now podcasts for years, and I own a copy of SpinRite myself.)

(Off topic ... I do like this XenForo Forum software!)

Colin P.

 

[jgreco]

(Off topic ... I do like this XenForo Forum software!

Well, nobody's perfect

 

[Ericloewe]

Well, nobody's perfect

As sucky as it is, it's still more usable than vBulletin (in most cases) or *cringe* custom forum software.

Seriously, have you ever seen the airliners.net forums? It's a custom solution of theirs that somehow doesn't implement such basic features as multi-page threads, instead infinitely growing a single page with most of the content loaded upon request until a moderator manually locks a thread and opens a new one when it reaches some 200-300 posts.

It's kinda like infinitely-scrolling websites, but with basic functionality like not having to always load all content posted after the one you're looking for with no way to garbage collect it.

 

[jgreco]

As sucky as it is, it's still more usable than vBulletin (in most cases) or *cringe* custom forum software.

Seriously, have you ever seen the airliners.net forums? It's a custom solution of theirs that somehow doesn't implement such basic features as multi-page threads, instead infinitely growing a single page with most of the content loaded upon request until a moderator manually locks a thread and opens a new one when it reaches some 200-300 posts.

It's kinda like infinitely-scrolling websites, but with basic functionality like not having to always load all content posted after the one you're looking for with no way to garbage collect it.

Hey, I was fine with Usenet. I'm not a real big fan of all this webcrap.

 

[CSP-on-FN]

Well, nobody's perfect

... dwelling off topic ... I'd almost forgotten those deep deep Usenet hierarchies!

So far I like this Forum software better than (for example) the new(ish) Macrium Reflect Version 6 Forum (which could be trying a bit too hard to be "new and fresh" IMO) and I think it's still better than the recently revamped but still unavoidably 'mature' Nikonians Forum.

(They're both genuinely nice communities of course. Never mind the medium that we / they use to communicate.)

This Forum is blissfully easy to navigate ...

(Edit: Sorry jmanin to have pulled your thread so far off your point!!!)

Colin P.

 

[jmanin]

:)

... dwelling off topic ... I'd almost forgotten those deep deep Usenet hierarchies!

So far I like this Forum software better than (for example) the new(ish) Macrium Reflect Version 6 Forum (which could be trying a bit too hard to be "new and fresh" IMO) and I think it's still better than the recently revamped but still unavoidably 'mature' Nikonians Forum.

(They're both genuinely nice communities of course. Never mind the medium that we / they use to communicate.)

This Forum is blissfully easy to navigate ...

(Edit: Sorry jmanin to have pulled your thread so far off your point!!!)

Colin P.

Not a problem. I've been reading this forum for a couple of months now, gathering information and learning. I really appreciate all the time and effort people put in to contribute to this forum. I just wanted to give a small contribution back hoping that it may help someone. Besides, I found it very entertaining so far. Not much else I can do, I think I have 3-4 hours left on the bad blocks phase so I'm just sitting here twiddling my thumbs.