Hello,

My current array is running out of space.

3TB Parity + 5 disk (3x 3TB, 2x 2TB)  Many of the drives (including parity drive) are ST3000DM001 - I know a lot of people post to avoid these drives now.  I have one open sata port I have been using for a pre-cleared drive but one of the ST3000DM001 just started giving me SMART warnings so I'm rebuilding that drive with the pre-clear drive.  So when that's done and the old one is removed, I'll have an open port.

 

I found reference to WD RED and IronWolf drives in the forum, so I'm looking at replacing the parity drive with one of these, WD Red has slightly lower price right now. 

QUESTION 1:  Do I get the 4TB or 6TB drive now for parity?  - I'm leaning toward the 6TB as they are nearly same $/tb but hesitating because it is $84 more.

 

One of the 2TB drives (Hitachi_HDS723020ALA640) gives me a temp warning 46C once or twice a week, the rest of the drives are running 35C-41C.  I expect this will be the next data drive to be replaced. No other warnings or flags on this drive.

QUESTION 2: Should I pre-clear the old parity drive (3TB) and use this to replace the Hitachi drive?  This will give me the additional space I'm looking for since I'd rather not add a drive to the array since it would fill all the sata ports on the mainboard and controller card.

 

Any good deals on Data drives right now?

 

 

 

My two cents.  IF your array is almost filled, use the 6TB drive.  IF your fill rate will give you enough room for a two years, go with the 3TB.  (I would expect that even higher capacity drives will be available at that time and may be even cheaper per TB basis.

 

I would not replace that Hitachi drive just because it is running hot. (Hitachi  drives are known for their high reliability and long life!)  I suspect that it is a 7200rpm drive and they tend to run hotter than the 5400rpm drives.  I would investigate two things.  First, thoroughly clean the inside of your case and all of the fans.  And clean out that CPU cooler fins!  Second, look at ways to increase the air flow through the case.  Replace fans with higher CFM rated ones if necessary.  Doing that will increase the life of everything inside of that case!!!

Thanks for the reply.  I have three aux internal fans, plus CPU and Power supply fans as well as a pair of fans outside the case blowing heat away from the case.  So aside from the heat warnings on that one drive no other heat issues (I think). 

  Upgrading the parity drive won't actually give me any more space, I'm currently using 12TB of 13TB array.  So to make more space available I need to 1) delete old files 2) upsize data disks or 3) use the last sata port for another data drive.

 

-- Oh I just had an idea, can I use a USB external dock to pre-clear a drive (instead of keeping a sata port available for this).  I searched the forum and found this posting which indicates I can.

http://lime-technology.com/forum/index.php?topic=15561.msg145418#msg145418

 

So based on that info and Frank1940's suggestions I could leave the 2TB drive in place then make the old parity drive a new data drive, adding 3tb of space to the array.  - Thanks!

Now that UnRaid supports 2 parity drives I expect there is a new procedure for upgrading a good parity drive. Something along the lines of:

1) add second parity drive - system is protected by first while building the second.

2) remove old parity drive

 

I've searched but haven't found reference to a new procedure, is this still in coming?

You can do that, there's no procedure, just add parity2 and when done remove parity1.

 

There will be some limitations, like it's not possible to reorder disk slots with parity2.

Thanks for the reply.  I have three aux internal fans, plus CPU and Power supply fans as well as a pair of fans outside the case blowing heat away from the case.  So aside from the heat warnings on that one drive no other heat issues (I think). 

 

<<< snip >>>

  Upgrading the parity drive won't actually give me any more space, I'm currently using 12TB of 13TB array.  So to make more space available I need to 1) delete old files 2) upsize data disks or 3) use the last sata port for another data drive.

 

So based on that info and Frank1940's suggestions I could leave the 2TB drive in place then make the old parity drive a new data drive, adding 3tb of space to the array.  - Thanks!

I would still have a good look at the cooling arrangement inside of that case.  In any server application, your attention should focus on increasing the air flow across the drives.  Any fans at the back of the case should be blowing out and the only fans blowing in should be at the front aimed at the drives.  The reason I am stressing this is that I have not recall folks reporting heat issues with Hitachi drives and I would think your problem is addressable.

 

Good choice on the larger parity drive.  Eventually, those present data drives will fail and you will then be positioned to use larger (up to your parity drive size) data disks.  So that is the way to go. 

The choice of what size to use for upgrading your parity drive is purely up to you.  As you know, that will be the limit of the size drives you can use for data ... so in general you want it to be large enough so your array will provide the space you need for a reasonable length of time in the future.

 

Personally, I'd definitely go with at least a 6TB drive ... you may even want to consider the superb 8TB WD Reds -- very reliable helium-sealed units that perform very well.  They do, of course, cost more -- but they're getting close to $300 ($319.99 at both Newegg & Amazon at the moment) -- a lot better than the $375 I paid for a few not very long ago.

 

Regarding price of drives...wait till this coming Friday and Monday. (Black Friday/Cyber Monday)

You may be able to find a screaming deal on drives...assuming you are in the USA of course.

You can do that, there's no procedure, just add parity2 and when done remove parity1.

 

There will be some limitations, like it's not possible to reorder disk slots with parity2.

 

johnnie.black - Does you mean only that I can't change "parity2" lable to be "parity1" after removing the old parity?  Or is there more to your stated limitation?

 

I've precleared the new drive and just added it as "parity 2".  My original plan was to remove the old parity disk to add to array (increase capacity). But since I ordered the new parity drive, I've deleted a bunch (old backups, empty recycle bin) so now I'm only using 64% of my 13TB.  So after the second parity drive is  finished I have two options.

 

A. Remove the old parity drive to keep available as precleared preparing for future failed disk.

B. Leave it there as dual parity, when another drive fails, order one online.

 

Parity1 ST300DM001 3TB (Seagate)

Parity2 WD40EFRX    4TB  (WD-Red)

Disk 1 ST300DM001 3TB (Seagate)

Disk 2 HDS723020ALA640 2TB (Hitachi)

Disk 3 ST300DM001 3TB (Seagate)

Disk 4 ST300DM001 3TB (Seagate)

Disk 5 HDS723020ALA640 2TB (Hitachi)

 

Cache 1 ST31000524AS 1TB (Seagate)

Cache 2 HDS723020ALA640 2TB (Hitachi)

 

I know everyone hates ST300DM001.

johnnie.black - Does you mean only that I can't change "parity2" lable to be "parity1" after removing the old parity?  Or is there more to your stated limitation?

 

Besides that, you can't change disk slot order while maintaining parity (unlike with parity1) and it can be a little more CPU intensive during parity checks if you have a low end system, but excluding these "limitations" there's no problem using only parity2.

 

 

ok, well I would not think to change disk order for fear it would confuse the system. 

 

 

 

Parity1 ST300DM001 3TB (Seagate)

Parity2 WD40EFRX    4TB  (WD-Red)

Disk 1 ST300DM001 3TB (Seagate)

Disk 2 HDS723020ALA640 2TB (Hitachi)

Disk 3 ST300DM001 3TB (Seagate)

Disk 4 ST300DM001 3TB (Seagate)

Disk 5 HDS723020ALA640 2TB (Hitachi)

 

Cache 1 ST31000524AS 1TB (Seagate)

Cache 2 HDS723020ALA640 2TB (Hitachi)

 

I know everyone hates ST300DM001.

 

Not Really!!!  I have three of them that have provided over 3 years of service.  I know that they got a really bad rep from the Backblaze data but BackBlaze's usage of these consumer drives is(was) far more rigorous (24-7 spinup, constant head movement and high temperatures) than what most unRAID users subject their drives to.  Unfortunately, Backblaze is the only company that has ever shared reliability data about drives in a true operating environment so we are forced to use it if we want any indication of real world failure rates.  Undoubtedly, the  ST300DM001 are more prone to failure but I don't think that they are quite as bad as the Backblaze data seems to indicate.  Remember that ALL hard drives will fail...

 

As a word of discourse, I do have a spare 3TB WD RED ready to go if any of my drives should fail!

Another thing to note about BackBlaze => they basically buy the least expensive drives they can ... generally consumer grade units.  In fact, after the flooding in Thailand several years ago they paid a "bounty" for folks to send in drives extracted from external units (which are often less expensive than bare drive), just to minimize their cost.

 

When you have thousands of drives; a robust RAID setup; and don't mind the hassle of always having a few drives being rebuilt, that's not necessarily a bad business model.  But I think if there was good reliability data for the drives targeted to more robust operations -- NAS and Enterprise units -- you'd find that these are much better choices for most of us.