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Synology 1813+ which raid to use? two raid5 vs one raid 6? VS no raid and have backup every hour?

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August 5, 2013 11:59:24 AM

Hi I am in the process of building a backup server for my SOHO office. I only have 3 employees counting myself. We do a lot of CAD drawings, video editing. Things to back up:

- CAD drawings essential for work around 0.5T space
- Videos essential for work around 6.0T space
- other work related data - 0.5T
- Personal photos and videos - Cannot be replaced so crucial - 5.0T

Total Needed 12T and maybe another 3T extra just in case so I need a total of 15T
Have 8X3T drives
Which raid is the best solution for my purpose?
Raid 5 21TB data 3TB protection 1 drive fail
Raid 5 + Hot spare 18TB 6TB protection 1 drive fail
Raid 6.2 18TB data 6TB protection 2 drive fail
Raid 6.3 15TB data 9TB protection 3 drive fail (Is there such a raid that has 5HD with 3HD protection?)
Raid 10 12TB data 12TB protection 4 drive fail

No Raid 4 HD and have program to either synch or backup the data to another drive





My questions are
1. Backup strategy - where can I find back up strategies? ie. having multiple sets of backup in different locations? Is there a standard method that companies uses if the data is essential?

2. I currently have Synology 1010+ was using raid 5 on that and am running out of space. So I bought a 1813+ and 8 3T Seagate drives. My question is what raid should I use for the 8 bay. I was leaning towards raid 5, because you get the most out of any raid that would give you at least one drive failing rate. But since I am using 8 HDD, I thought the chances of that failing is much higher than a 5HDD raid 5. So should I use raid 6? or raid 5 with Hot swap? of two 4 HDD raid5s, if that I should get a NAS with less bays?
How about having no raid and have 4 disk with data and 4 disk basically mirroring the data so maybe that would mean 4 raid 0s?
a c 750 G Storage
August 5, 2013 12:14:12 PM

1. Backup strategy
- where can I find back up strategies? ie. having multiple sets of backup in different locations? Is the a standard method that companies uses if the data is essential?


Daily incremental, weekly full backup.
At least one backup copy offsite in case of fire/flood/theft.

Here is a strategy from Microsoft:
http://technet.microsoft.com/en-us/library/cc938488.asp...
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a c 812 G Storage
August 5, 2013 1:49:36 PM

for essential data arrays I use raid 1+0, unfortunately this barely meets your storage needs since you lose half the space so for your situation I think a raid 6 suits you best. 7 drives in raid6 with 1 hot spare would yield 15tb. I owuld suggest you buy another drive or two to keep spares on hand.

As for your backups, what backup solution do you have in place equipment-wise that is.
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August 5, 2013 2:26:36 PM

Thanks for your suggestions. I guess I could prioritize the importance of my data. For example, maybe just backup the irreplaceable types like personal photos, videos, customer info and WIP projects. And I could use raid 10, 1+0, Raid 6 + 2 tolerance, Raid 5 + hot swap.

I guess my follow-up question would be out of the 4 raids below, keeping in mind there will be a maximum of 5 users accessing the data at any one time.
Raid 10, 1+0, Raid 6 + 2 tolerance, Raid 5 + hot swap
1.What are the pros and cons of them?
2. Are there any SIGNIFICANT difference in performance? eq. loading 1 gig video
3. Does building or rebuilding Raid 6 w/ one protection vs Raid 6 w/ two protection take a lot more time?
4. How about Raid 6 w/one Vs Raid 5 with hot spare?
5. Does Raid 10 have same or very similar performance vs Raid 1?
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August 5, 2013 2:27:35 PM

popatim said:
for essential data arrays I use raid 1+0, unfortunately this barely meets your storage needs since you lose half the space so for your situation I think a raid 6 suits you best. 7 drives in raid6 with 1 hot spare would yield 15tb. I owuld suggest you buy another drive or two to keep spares on hand.

As for your backups, what backup solution do you have in place equipment-wise that is.


Does raid6 + hot swap mean there are 3 drive tolerance?
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August 5, 2013 2:40:47 PM

popatim said:
for essential data arrays I use raid 1+0, unfortunately this barely meets your storage needs since you lose half the space so for your situation I think a raid 6 suits you best. 7 drives in raid6 with 1 hot spare would yield 15tb. I owuld suggest you buy another drive or two to keep spares on hand.

As for your backups, what backup solution do you have in place equipment-wise that is.


Don't really understand what you mean by backup solution equipment? mean?

I am using sinology 1813+ for hardware, thinking of using the following:
Backup or Synch folder or Timed backup from Synology
Data back or File backup from Acronis 2010

Any suggestions? Thanks.
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a c 812 G Storage
August 6, 2013 6:56:56 PM

by backup equipment I was referring to: what will you be backing up to? The synology cannot backup to itself. its got to go somewhere.

raid6 is a 2 drive fault tolerant system. Hotspares means if a drive dies a rebuild using the spare begins immediately. if two drives fail and you only have 1 hot spare then the second failed drive cant rebuild until someone gets there and physically removes the failed drive and inserts a replacement.

raid 5 is a 1 fault tolerant system. theres no point in having 2 spares as losing 2 drives at the same time means you've just lost all your data. everything.

raid 10 is a bunch of raid1's (often two drive raid1's) merged into a raid0. speed is proprtional to the number of raid1's (ie 8 drive raid10 (four raid1's) is about twice as fast as a 4 drive raid 10) fault tolerance is odd but higher than 1 drive. I'll try to explain.

in raid 5 if you loose 2 drives all data is lost. in raid 6 its the 3rd drive that critical. In raid 10 you have to loose one of the raid1's. Considering an 8 drive raid10 which is four raid1's in a raid0. if you loose 1 drive the other drive in the raid1 pair keeps you up. of the remaining 7 drives there is only 1 drive that will definitely bring down the array and thats the mirror of the failed drive. So there is a 1 in 7 (14.3%) chance of a second drive failure bringing down the array (unlike the 100% chance in a raid5). Lets say another drive fails but its not the critial one. That means two of the four raird1's are degraded (only 1 drive in each pair working) and the other remaining four drives are ok. now if two raid1 pair are degraded then if either of those 2 drives fail the array is lost but that is 2 out of 6 running drives or a 33.3% chance of loosing the array versus 100% of a raid6 failing on the third failure. Now imagine if you had 24 drives in raid10; the chance of 3 drives taking out your array drops to 2 in 22 or about 10%

unfortunately an 8 bay unit doesnt leave you much choices.
Raid6+2 (hotspares) gives you 12tb space = no room to grow.
Raid10 (all 8 drives) gives you 12tb space = no room to grow.
raid6+1 (7 drives in raid6 +1 hotsapre) gives you 15tb space.
raid 5+1 (7 drives in raid5 +1 hotspare) gives you 18tb space which is the most space and the least fault tolerant imo.

any chance you could increase to larger (more drives) unit? You never mentioned budget.

as for speed, raid 6 is by far the slowest in writes but has decent read speeds.
raid 5 is the next quickest in writes and has good/great read speeds.
raid10 is the fastest reads & writes but the full potential is not achievable with this unit. This unit is capable of about 100MB/'s thanks to the gigabit ports. There is an option to link all the ports together and get upwards of 300MB/s from the unit but no one I know has done it. Several have teamed two ports together to get about 200MB/s. (all your equipment would need to support port teaming/aggregate linking including the pc's) For comparison an 8 drive raid10 is capable of 600MB/s+ in sequential reads.

edit - if you do loose a drive and the unit is rebuilding it will be horribly slow. its also best practice to not use it while its rebuilding.

And to answer your other question, no - having hotspares does not increase the number of drives you can lose at any one time. It only effects when the rebuild process begins which directly effects when it will complete and you can get back to work.
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August 7, 2013 5:45:16 AM

Okay I guess I should give you the whole picture:

Equipment owned:
SOHO
DS 1813+
DS1513+
DS 151 (5 bay extension)
DS 410j
Office
DS1010+

Seagate 3TB Barracuda X 12
Seagate 2TB Barracuda X 12
WD Red 2TB X 8

Current Setup:

DS1813+ 8 x 3 TB Synology Raid with two drive tolerance (New so not in use for now)
DS 1513+ 5 X 3TB plus DS 510 3X 2TB Barracuda raid 5 ,250G X 2 no raid (Use to put essential data that I cannot use), also have all the movies and music on this)
DS 410j 5 X 2TB barracuda (Used to backup DS1513 8TB raid)
DS 1010+ WD red 2TB X 5 Raid 5

So this is what I own now, won't bee a problem if I exchange some of my stuff in office with what I have at Home.

Office: 40ppl sharing 8TB for email, photos, CAD drawings and so on. Most users are only using light office and internet. 4 designers using CAD.

Let's just focus on my home. I want something that is reliable and having the NAS down would not be the end of the world. I say there are roughly 4TB of data that I CANNOT loose.
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a c 812 G Storage
August 10, 2013 2:03:44 AM

given you have space to backup your critical files, I would go with the raid5. 7 drives in raid 5 gives you 18tb of space. Thats plenty of room to grow.
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