411J and 4 WG Green Disks-worried-adwise seeked

[Sukisum]

Hi
Im new to this forum and using NAS.
I purchased my first NAS a Synology 411J 1½ month ago (without disks).
I already have a WD Caviar Green 2TB (WD20EARX)drive, so talking with the dealer I bougth another 3 2TB disks (WD20EARX).
Also I checked that the WD Caviar Green are recommended on the Synology Web page. And many dealers sell them with the 411J.
I set the thing up in a Raid5 setup.
Everything has worked fine, and Im now in the process of filling stuff pictures and audio to the NAS.

Then 2 days ago suddenly the NAS started to beep, and it turned out, that one of the disks failed.
I looked on the net, and then I removed the faulty disk, and put it in again. And then I was able use the repair on the disk control screen.
The consistency check is now 100%, and now everyting is fine again and all the diskes are running normal.

Now I have looked on the net regarding the issue of LLC count. My diskes react different to this.
Look the schedule below:
Disk 1, Type=WD20EARX, RRER=0, SUT=6091, POH=697, LCC=189
Disk 2, Type=WD20EARS, RRER=163, SUT=1216, POH=886, LCC=676
Disk 3, Type=WD20EARX, RRER=0, SUT=5525, POH=673, LCC=37570 (This disk failed!, but works now)
Disk 4, Type=WD20EARX, RRER=0, SUT=6416, POH=673, LCC=37580

Explanation:
RRER = Raw_Read_Error_Rate
SUT = Spin_Up_Time
POH= Power_On_Hours
LCC=Load_Cycle_Count

The idea with a nas and raid 5 was to have all data collected safe and like a backup in Raid 5, in the unlikely event that a disk should fail.

Im worried reading on the net, is WD20EARX no good for NAS and especially Raid 5?

Please give me comments om this.

[deerpark]

First of all I have to say, a RAID setup should not and cannot replace a real backup. A RAID setup might not save you if something happens to your NAS. It could get struck by lightning, stolen, I've even heard of one guy who had a catastrophic hardware failure in his NAS that left all the drives in his RAID setup unreadable. If you have data you can't afford to loose you should always back that data up to a separate drive, preferably stored away from your NAS.

Regarding the drive that failed. What happened might have been a sector going bad. When this happens a modern hard drive have several spare sectors available, as long as one of those are available it will swap out the bad sector and continue as normal. While the hard drive is trying to retrieve data from the bad sector, to write to the spare, it won't be available for normal operation. This can make a RAID fail as the system will think the drive have failed because it isn't responding.

But as like I said, as long as the drive have spare, good sectors it will function as normal again once the spare has been replaced. This is probably why the disk is now working.

What I would do is use the S.M.A.R.T. tests under HDD management to make sure all the drives are functioning normally. If they can pass the extended test they should be safe to use.

I would be a bit worried about the high LCC though. Have your tried the fixes suggested for WD drives to remedy the LCC problem?

BTW. You can read a better explanation on why RAIDs may fail during a sector swap here:
http://forum.synology.com/wiki/index.ph ... -Class_HDD

[Sukisum]

Hi

Thanks for the answer. I have looked at the WDIDLE3 fix process. It seems to be a bit complicated with removing discs from the computer etc.
And I have read that it only should be used for empty drives?

Question is there som other way. Maybe the power settings in the synolygy DSM ? could that improve things?

Meanwhile I have asked also in the WD forum. And according to this WD Green Discss is a no go for Raid 5. Loook here:
http://community.wdc.com/t5/Desktop/WD- ... d-p/289408

Question is, maybe I should go back to the dealer and say that he has sold me "no go" discs together with the Synology 411J (but the Synology recomends these discs?)

Please comment

[maxxfi]

The green drives probably are a poor choice if you have a *hardware* RAID.
With a RAID controller, you need disks that don't slow down to reply when they find an internal error, otherwise they are kicked out of the array.

In Synology (and other similar brand) NAS, there is a software RAID, and these requirements
are more relaxed. That's why Synology accepted those green disks into their Compatibility List
(and many users on this forum seem to be ok with those disks).

That said, if you want some additional 'peace of mind', it would be better to choose the RAID-edition version of those same disks.

[Sukisum]

Hi
Thanks for the answer
Maxxfi, so you think it migth be ok to use the WD Green caviar disks. So maybe if I just follow the disks and especially the Load_Cycle_Count, the it should be ok.

You say the "Raid-edit version" of the disks (WD20EARX)

What does that mean?
I have tried to google Raid-edit version" and WD20EARX without result.

[maxxfi]

Check for instance about the RE4 and RE4-GP type of disks

[synGuy]

Thanks for the answer. I have looked at the WDIDLE3 fix process. It seems to be a bit complicated with removing discs from the computer etc.
And I have read that it only should be used for empty drives?

I have 5 WD Greens in my 1511+.
My WD15EADS has over 450000 LCC, still kicking.

In the lastest DSM versions (3.2 1922 I believe) Synology has integrated the idle3 process into their software, meaning DSM automatically disables the parking.

Since upgrading DSM (and fully powering down) I haven't had a single LCC count increase in 3 days.

[Sukisum]

Hi SynGuy

I also run DSM version 3.2-1922 on my 411J.

2 questions:
1. Is there some setting that needs to be set in the DSM in order for the Synology idele3 process to run?
2. Do you also run Raid 5?

Since I had the incident with the failing disk, I changed the power setting from "low power use" to "quiet-power use" since then the LCC has only increased with 3 for all disks. See the Smart info below.

Disk 1, Type=WD20EARX, RRER=0, SUT=6091, POH=697, LCC=189(192)
Disk 2, Type=WD20EARS, RRER=163, SUT=1216, POH=886, LCC=676(679)
Disk 3, Type=WD20EARX, RRER=0, SUT=5525, POH=673, LCC=37570(27573) (This disk failed!, but works now)
Disk 4, Type=WD20EARX, RRER=0, SUT=6416, POH=673, LCC=37580(27583)

Best regards

[Sukisum]

Hi again

Well now disk 3 just failed again

Im gonna take the failed disk to the dealer and discuss this with him