Bought two Synology DS1512+ units - what is the best configuration?

[LaCrosse]

Hi all,


Having never owned a NAS unit before, I've decided to start off by getting two of the DS1512+ units by Synology. I've read the excellent "Smart SOHOs Don't Do RAID" article which motivated me to play it safe and perform backups instead of counting on RAID to save my precious data. That being said, I am a newbie to the NAS scene and would appreciate some advice about the best way to set up my 2 new units. Should I use JBOD or will that cause me to lose all of my data on one NAS if only one HD fails? Should I use RAID at all or simply do the 1:1 backups from one DS1512+ to another?

Purpose of the NAS: video streaming to my TV; storage of my pictures, videos and music; backup of all the data on my 2 laptops and 1 desktop.

Hard drives: five 4TB hard drives in one NAS and five more 4TB hard drives in the other.

My order of priorities:

1) The safety of my data.
2) Maximizing my storage space (a close second).
3) Transfer speeds (ideally I'd like to be able to simultaneously stream two 1080p mkv files or two BluRay images over my gigabit network).


Thanks!

 

[thiggins]

You jumped in at a pretty high price point for your first NAS(es)!

If you set up one NAS to automatically replicate to the other, you could take some risk and use JBOD. If one drive fails, you will lose the volume, however.

Safest configuration would be RAID 6, which can tolerate two simultaneous drive failures. Downside is that it is the least space efficient. You can use Synology's RAID Calculator to see what other configurations yield for capacity.

If the safety of your data is paramount, one of your NASes should be at another physical location to protect against fire and theft. And both should be on UPS.

 

[tipstir]

I've gone with JBOD myself as the RAID mirroring limits the second drive. With two volumes acting as one volume is another choice or separated is another choice. Depends on your needs.

 

[LaCrosse]

Thank you both for responding. Indeed, these units are pricy but based on my research they are somewhat like Apple products - well designed, well thought-out and likely to give their users years of trouble-free use.

I am going to read up more on Synology's own Hybrid RAID (SHR) solution but it appears that there is no kind of RAID that doesn't "cost" me additional storage except for RAID 0. After making the choice to get a second NAS to backup the first, losing even more potential storage space to do parity feels painfully wasteful. What are the pros of going with JBOD as opposed to RAID 0 if I am to perform regular backups of one NAS to another?

What concerns me about RAID 0 is the chance that one of the HDs on my second NAS fails as I am restoring the volume on the first, primary data. It appears that will destroy anything I have saved on either one of the NASes.

Would anyone be kind enough to share a mathematical formula (or an accurate online calculator) that would allow for calculation of the risk of losing all the data in different kinds of RAIDs? For example, if I know that one HD has a 4% chance of failing within a year, what are the chances that a 5-drive RAID0/RAID1/RAID5/RAID6 array loses all of its data? Or if someone knows of a formula involving the mean time between failure (MTBF), I would equally appreciate it. I've looked online but it seems there seems to be quite a bit of conflicting information out there about how this kind of math would be done.

Thanks!

 

[thiggins]

Yes, all RAID uses storage for the parity data it must keep.

Both JBOD and RAID0 volumes die if one drive fails. RAID 0 is supposed to provide higher performance than JBOD, but I doubt you would see it.

I can't provide you with the calculator you seek. More protection comes at a cost. Only you can decide how much your data is worth.

Note that two NASes at the same physical location expose you to fire/theft risk. For higher protection, critical files should be backed up off-site.

 

[MacUser]

two Synology DS1512+ units

We have Apple environment and a lot of single ext. Hard-drive.
Did buy the same two Synology devices like >LaCrosse<, but just 4x very fast Hitachi 4TB Enterprise 24/7 Hard-drive for our Academy and Home-office. And a intelligent UPS on each side with all power failures and blackout happen this year in our area.
I did still not install the system, there is little about how to setup the two NAS on two different places: Server - client or connecting the two NAS via VPN or other configurations.

When I use the Backup config. - can I still use both DS1512+ for streaming music or movies on both sides? How about Raid on both sides?

If I can setup the system on a way so I can use the same documents in my home office and in Class for our Students, using e.g. Sonos Speakers and stream music in some or all rooms, show short films or presentations.

Preparing at home and use the material at work or in other Institutes or other countries - conferences etc.

What will be a real good solution : RAID and how set up two NAS on two places?
I will be very grateful for any link or help here.

Cheers

 

[stevech]

I use two volumes, on separate drives, with periodic backup across the two. This provides the backup that RAID lacks. And the Time Backup protects from human error.

External backup to an eSATA or USB3 drive is essential for protection from theft of the NAS.

 

[PrivateJoker]

@Macuser - can you clarify for me, these two DS1512s are in the same physical place but you want to do different things with each one?

SHR mode is a good, fast, flexible mode for redundancy between multiple drives within the same NAS.

Personally I have created a separate volume tied to each machine I want to create a TimeMachine for, but I think other people have done same volume for multiple machine TM volumes, but individual volumes give you some protection from other users and it's easier for me and how I like to do things. Then you can create more widely shared volumes for documents & av media.

Currently I backup my entire Synology weekly to an attached 3TB USB 3.0 drive (which I rotate off site), but I'm about to get another external drive and do weekly full machine disk cloning to it w/ SuperDuper so in case of failure I have TimeMachine on the Synology and if the Synology itself fails I can just take my (yet to be purchased) alternate external drive (that is shared and plugged into the Synology normally and restore via SuperDuper. The Synologys allow you to utilize external drives formatted w/ HPFS (MAC journaled file format). And I typically get faster R&W to external drives plugged into the Synology than if they were plugged in locally. I want to do this because I've been in scary situations in the past where a RAID is corrupted or in some way inaccessible and having a backup of the RAID on an EXT3/4 formatted drive is of limited help because I can't just plug that volume into any local machine.

 

[MacUser]

two Synology DS1512+ units

" can you clarify for me, these two DS1512s are in the same physical place but you want to do different things with each one? "

We have two exactly the same DS1512+ with 2x 4TB inside each - on TWO DIFFERENT places (work and home office). We need to have the same content on each of them and when making changes, it should be automatically also on the other NAS.
Did buy them dec 2012 and they are still not installed... http://forums.smallnetbuilder.com/images/smilies/rolleyes.gif
http://forums.smallnetbuilder.com/images/smilies/confused.gif

My Question was:
With totally 4x4Tb =16 TB, 7800, 24/7 Enterprise Hitachi drives - Raid with two 4 Tb HDD inside each NAS and synchronizing with the other NAS, will result in totally only 4TB for content. The rest is for Raid / mirror. Is pretty expensive to have more of this drives, so how can I install this system so it can easily be extended, when new drives are available.
Do anyone know any smarter solution? Any ideas?

Btw I use Apples own solution for TimeMachine, independent to the NAS for our
iMac and MacBookPro. Its only all the educational stuff for all our students, music, film, pictures etc.

Thanks for reading so far

Cheers

 

[PrivateJoker]

If you're using RAID 1, and mirroring it off site to an identical unit, you should check out the list of Synology recommended drives and cross check that to Newegg & Amazon, and find the best GB for the $. I can't think of a compelling reason to maintain a super high standard of drive, when it is RAIDed and mirrored and you have a goal of economical expansion.

http://www.synology.com/support/hd....ducts&hd_select_bay=4&hd_select_ds=DS1512+#96

I don't know which Hitachi 4TB "24/7" drive you have, but I'm going to use one of the enterprise drives from the Synology list (HUS724040ALA640), $350 @ Newegg ($.0875 / Gb), for this comparison.

For comparison, the WD 3TB Red (WD30EFRX), also on the Synology approved compatibility list for your NAS, $135 today @ Newegg ($0.045 / Gb), almost exactly half as much for same level of redundancy and mirroring.

 

[Terry Kennedy]

We have two exactly the same DS1512+ with 2x 4TB inside each - on TWO DIFFERENT places (work and home office). We need to have the same content on each of them and when making changes, it should be automatically also on the other NAS.

One very important consideration is how fast the slowest network connection is. Even a high-tier cable company Internet service is something like 50Mbit/sec down, 10Mbit/sec up. That means that if your work has a connection like that, it will only be able to send (absolute best case) 1.25Mbyte/sec, 4.5Gbyte/hour. Less if your download speed at the home office is lower. And you may want to limit replication activity to off-hours so it doesn't compete with normal daytime Internet usage (if you don't need immediate replication).

The next thing to think about is whether you need bidirectional replication (a change made to the home unit gets replicated to the work unit, while a change on the work unit also gets replicated to the home unit) or if unidirectional replication is sufficient (one is a backup for the other, also providing faster local access to files). Bidirectional replication on a single large data partition is far more complicated than having 2 partitions (let's call them A and B) where changes to the office's A go to the home's A, and changes to the home's B go to the office's B. Office users should not change files on B and home users should not change files on A.

Lastly, if you're going to be copying existing data to these units (rather than starting from scratch on empty ones), you'll be a lot happier having them both in one location temporarily, so that replication can happen without the delay from the Internet connection. Once you have them filled and have verified that your replication is working as desired, you can move them to their final locations.

 

[stevech]

rSync is often used.

indeed, ISP uplink speeds constrain what's practical, in terms of volume after the initial sync.

As you know, most ISPs' upstream speed is a small fraction of the downlink speed, by intent.