titusc wrote:Hi, given QNAP uses Linux software RAID, will the QNAP series of NASes drop a disk out from the array if it's trying to recover from a bad sector and taking its time (ie more than 10 seconds)? Since with enterprise drives it has TLER it'd opt to indicate a block as unrecoverable and let the RAID to recover it from the other disks, the cheaper non enterprise drives don't have this feature and will keep trying for a long time (ie exceeding 10 seconds if required). Would this cause a problem with QNAP's NASes?
I'm going to be using RAID 1 only. Can't bother with RAID 5 as I'm only after redundancy.
BTW can I have 4 drives all in RAID 1?
titusc wrote:Thanks but I'm looking for all disks in the array containing the same information. Is this possible? All 3 or 4 drives have identical content?
Not possible as far as I know. A 3-disk RAID 6 offer the same redundancy as a 3-disk RAID 1 would. A hot spare could be added for the highest supported disk redundancy in a 4-bay model.titusc wrote:Thanks but I'm looking for all disks in the array containing the same information. Is this possible? All 3 or 4 drives have identical content?
Not possible as far as I know. A 3-disk RAID 6 offer the same redundancy as a 3-disk RAID 1 would. A hot spare could be added for the highest supported disk redundancy in a 4-bay model.
Sorry about that. Since the configuration you want isn't supported I was trying to be creative but forgot about the requirement to have at least 4 disks in RAID 6.titusc wrote:RAID 6 requires minimum 4 disks and can survive 2 disks outage.
Ahh, the old URE-myth. Okay, let's deal with that again.The issue comes with the re-silvering operation scare given the high URE to TB ratio.
2 TB desktop disks have been used in RAID 5 and RAID 6 for many years now. Since about 18 months there must be several thousand of arrays running with 3 TB desktop disks and I haven't noticed any alarming increase of failed rebuilds. I don't expect it to become terrible with 4 TB disks either.Shouldn't be a factor if we're talking about only four 1TB disks.
Well the comparison isn't really fair. I guess you intend to have the disks to store data and then you must be aiming for some storage volume. Considering the configuration you talk about I guess it is 3 TB? With a RAID 5 you could use 4*1 TB disks to get to that same number and suddenly we're back at your trusted 1 TB disks. With RAID 6 you could use 4 of the very well proven 2 TB disks to get 4 TB storage and have the same 2 disk redundancy as in your 3*3 TB RAID 1, all for less money!Also, if the option of having 3 disks all containing the exact replica in a RAID 1 setup, I only need to buy 3 disks and can loose up to 2 disks. This is in comparison of using 3 disks in a RAID 5 setup and only able to loose 1 disk.
True, but read speeds will be better for RAID 5 because of the striping. It's of course a matter of personal preference which is most important.Besides from an IO perspective, write speed for RAID 1 will be quicker than RAID 5 since it doesn't have to calculate parity.
Yes.Are we able to use non enterprise disks in these NASes?
They are.If they are using software Linux RAID...
It depends on how long the disk is trying to recover but I can't give you any specific numbers because I don't know the exact timeouts. I only know that many, including myself, are running RAID 5 with desktop disks and it works well....are these NASes going to drop a drive out of the array if a non enterprise disk is trying to recover from a bad block for an extended period of time (ie over 10s)?
As far as I know the Seagate compatibility problems are limited to some newer desktop models. Apart from the WD RE4-GP (it may not not be a coincidence that it doesn't seem to be available any more), I haven't noticed many problems reported by Qnap-customers here in the forum with any enterprise disk from any manufacturer.titusc wrote:Seagate disks are problematic (at least based on what we see on this forum).
Yes i was a bit confused about that you had prices on those older models..titusc wrote:Hi, just dropped to a retail shop but was told the HDT721010SLA360 and HDS723015BLA642 are legacy models and currently they only have HDS721010DLE630 on market as listed on the following page:
Well that's because it isn't a Constellation model. If you google it you'll notice that it is a now phased out Barracuda ES.2 model. It's still an enterprise disk but again I was surprised to see you presenting a price on it. This is documentation on the disk, that appeared on my first google page.Also trying to search for Seagate's ST3500320NS online it's no where to be found on their official home page list of their Constellation drives.
Generally I would imagine any new compatibility testing is concentrated on the currently best selling models and that is most likely 2 TB disks and higher today.Ignoring the Seagate for the moment, I am currently stuck in not knowing which drive to choose. This is becasue the HDS721010DLE630 despite as being new it isn't listed on the compatibility page.
The HDS721010DLE630 is probably an older model that have just been updated with a new interface. It's not likely, but unfortunately that change may make it incompatible. My guess would be that you're on your own trying it out.Any idea if HDS721010DLE630 would work with the TS-459 PRO +?
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