NAS Drive

LunarMist

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#1
I finally bought a basic NAS and some drives. Should the drives be fully tested separately outside of the device or does the NAS do that? Thanks.
 

blakerwry

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#2
After having been burned a few times, I like to burn-in test all drives individually. Most NAS devices do a poor or non-existent job of tracking drive health. For example, a drive that fails the SMART self-test does not trigger any alert on an HP home server I have. The extended/long SMART self-test (typically an hour) is probably sufficient and is non-destructive. If the drives are empty, a DBAN wipe (destructive) would be a good burn-in test.
 

Mercutio

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#3
I usually run 2TB+ drives through Seatools long diagnostic before I put them into service, no matter how I intend to use them.
Seatools will test multiple drives in parallel, though it doesn't like being used on systems with more than 10 connected drives.
 
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#4
I suppose it depends on how good your backup infrastructure is. If it would be inconvenient to lose the entire array (meaning, more drives than you have redundancy fail within the rebuild time), run the tests. I don't, and am lucky enough to have never lost an array, but that is luck that will change eventually.

Of course, there is still a chance of failure (backups!), but if restoring from those backups would be a PITA, may as well run the tests.
 

LunarMist

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#6
I suppose it depends on how good your backup infrastructure is. If it would be inconvenient to lose the entire array (meaning, more drives than you have redundancy fail within the rebuild time), run the tests. I don't, and am lucky enough to have never lost an array, but that is luck that will change eventually.

Of course, there is still a chance of failure (backups!), but if restoring from those backups would be a PITA, may as well run the tests.
This is my first experience with the NAD, so I'm starting with using it for the backup of 4-5 main data drives. It's rather slow due to the GbE, so I don't see much purpose for this type of unit for primary data.
I'll keep the normal backup drives for a while until I'm confident this thing is working well enough. I'll test the drives outside before storing any real data, but that will take a few days.
How do you test the rebuilder, pull one drive and format it in another computer, then return it?
 

CougTek

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#8
It is the SynoLogic 1515 and 4x8TB WD RED.
The DS1515 or the DS1515+? The DS1515 is enough for your needs IMO.

About the slow speed transfer limited by the gigabit port, you have four LAN ports that you can combine (link aggregation). It won't improve transfer speed from a single device, but it will allow full gigabit transfers from multiple devices simultaneously.
 

LunarMist

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#9
It is the DS1515 which is newer and rated for the 8TB drives. Link aggregation will not be useful in my case.
 
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#16
If you want fast rebuild times and 10GbE that doesn't cost a fortune, what you want is called a PC.
I'll second that. Synology does have several great NAS units that have 10GbE (or support adding cards) and higher end CPUs. The DS3615xs is a great unit; at a fairly competitive cost for what it is. I've installed them and have no complaints. $3200 before drives and before 10GbE NIC is probably more than you want to spend.

Rebuild time is a pain, but doesn't happen often. 10GbE is nice, but make sure that your other systems can support significantly more than GbE before putting too much value there.
 

LunarMist

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#18
I don't want a RAID in the computer. I would need 10 bgE for primary data. It sucks saving to the NAS at 100MBs.
 

CougTek

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#19
I'll second that. Synology does have several great NAS units that have 10GbE (or support adding cards) and higher end CPUs.
QNAP's NAS units are typically cheaper at any given performance level.

For instance, this QNAP NAS is a very powerful unit for only 1227$. You'll need to buy the 10GbE NIC separately, but there are several compatible models and you could probably get one cheap on eBay. You'd save money with a pair of SFP+ NICs IMO, one in the NAS, one in your PC.

There are cheaper NAS with 10GbE ports, but they often are under-powered and cannot fully benefit from the faster network connection.
 

LunarMist

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#20
QNAP's NAS units are typically cheaper at any given performance level.

For instance, this QNAP NAS is a very powerful unit for only 1227$. You'll need to buy the 10GbE NIC separately, but there are several compatible models and you could probably get one cheap on eBay. You'd save money with a pair of SFP+ NICs IMO, one in the NAS, one in your PC.

There are cheaper NAS with 10GbE ports, but they often are under-powered and cannot fully benefit from the faster network connection.
Thanks. I'll check into it for the future. I would probably get the 8-bay model and use the RAID 6. With the drives and card it would be about $4K.
 

blakerwry

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#21
If you don't really need network attached storage (NAS), you might look at direct attached (DAS) options. We use external eSATA or SAS enclosures that allow you to access large numbers of external drives as if they were internal. If you don't already have eSATA or a SAS card with external ports, add this to your cost along with the enclosure and drives.
 

blakerwry

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#22
Something like the Norco DS-12D runs ~ $500. An basic LSI controller (non-RAID or RAID 0/1/10) with external SAS connections will set you back ~$300; A fancy one w/ cache + RAID 5/6/50 maybe double that.
 

LunarMist

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#23
I tried eSATA drives and internal RAIDs some years ago, but it was a cluster for the most part.
I like the idea that the NAS can run independently of the computers so I could access it from either one.
For now I will try to give the Sinology a really hard workout and use it as the backup target for a while.
I have to figure out to turn it on at distance. IIRC there are AWOL commands for it.
 

LunarMist

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#24
I've almost completed backing up data to the RAID, but now realize that one of the wrong drives is in the array. :crap:
Party consistency is now at 95%. I assume that and the copying should finish before I replace the drive.
Then it will take a few days to rebuild if I understand correctly.
 
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#25
I've almost completed backing up data to the RAID, but now realize that one of the wrong drives is in the array. :crap:
Party consistency is now at 95%. I assume that and the copying should finish before I replace the drive.
Then it will take a few days to rebuild if I understand correctly.
Yup. Will be a good test of the redundancy, just pull the drive and swap it live. Make sure you know which drive, first.
 

LunarMist

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#26
Yup. Will be a good test of the redundancy, just pull the drive and swap it live. Make sure you know which drive, first.
It's the drive not for NAS, so that was pretty obvious. ;)
The NAS beeped incessantly with a different drive installed. I had to disable the beep and start the rebuild manually from the web interface.
The Repairing (Checking parity consistency...) is at 11% after about 100 minutes.
 

LunarMist

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#27
It's the drive not for NAS, so that was pretty obvious. ;)
The NAS beeped incessantly with a different drive installed. I had to disable the beep and start the rebuild manually from the web interface.
The Repairing (Checking parity consistency...) is at 11% after about 100 minutes.
It completed successfully after 16.5 hours. I'm not clear on whether that checks all disks completely or only the data.
 

blakerwry

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#28
It completed successfully after 16.5 hours. I'm not clear on whether that checks all disks completely or only the data.
RAID operates at the block layer (or bit layer for some raid levels) so the controller and disks generally don't know what blocks contain data that are relevant to the file system/OS. A rebuild thus requires reconstruction from all disks in a RAID5/6 array or from the appropriate mirror disk in a RAID 1/10 array.

The exception to this rule might be SSDs which track the mapping between LBAs and the underlying flash so they can implement wear leveling and TRIM optimizations. However, even though an SSD may know that an LBA is no longer used, this information is probably not tracked by the RAID controller in a manner that allows optimizing the reconstruction process.
 

LunarMist

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#29
RAID operates at the block layer (or bit layer for some raid levels) so the controller and disks generally don't know what blocks contain data that are relevant to the file system/OS. A rebuild thus requires reconstruction from all disks in a RAID5/6 array or from the appropriate mirror disk in a RAID 1/10 array.

The exception to this rule might be SSDs which track the mapping between LBAs and the underlying flash so they can implement wear leveling and TRIM optimizations. However, even though an SSD may know that an LBA is no longer used, this information is probably not tracked by the RAID controller in a manner that allows optimizing the reconstruction process.
Thanks. I understand correctly, during the repairing activity the normal drives are all being read and the new drive is fully being written. 16.5 hours is not too much longer than the time required to write a full 8TB drive directly.
 

blakerwry

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#30
Thanks. I understand correctly, during the repairing activity the normal drives are all being read and the new drive is fully being written. 16.5 hours is not too much longer than the time required to write a full 8TB drive directly.
I think that's a pretty respectable time also. We occasionally have to rebuild 600GB 15k SAS drives in a RAID10 and they often take several hours to the better part of a day to rebuild on a PERC controller (defaults to 30% rebuild rate). The last time I had to rebuild a 7.2k RPM SATA drive it took roughly a day, IIRC.
 

LunarMist

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#34
The NAS password is lost every time it reboots. Rebooting the computer has no effect. Is that normal?
It is annoying, because one must log into the NADS to power it down.
 
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