Hikvision raid5

B

babiskarg

n3wb
Sep 12, 2016
3
0
Hello ,

I need to have RAID 5 for three IP cameras with 2MP /15fps /6000Kbps resolution .

The duration of total record time that i need is 458 hours (20 days).

I know that for raid 5 ,i need minimum 3 hdd and to calculate capacity use type
(N-1)*M
But how can calculate days?with disk calculator disk tool of hikvision?
Thanks
 
Here you go...

bp2008 said:
Calculating this is really easy once you understand that it is just simple multiplication and division and understand how units of measure work (this is like elementary school math).

However many cameras you have, add up their bit rates. Example: 4 cameras at 4 Mbps each = 16 Mbps. That is your total bit rate. Lets assume you have 6 TB of space. Then go to google and enter: 6 TB / 16 Mbps and google tells us that 6 TB would hold 34.7222222 days of video if the bit rate was 16 Mbps. You just have to not get the units wrong. TB = terabytes. Mbps = megabits per second. If you screw up and search for "6 TB / 16 MBps" for example you'd get the wrong answer just because you capitalized a B turning megabits into megabytes.
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raid is dead, just run a big jbod.. especially for surveillance video.

are you really going to let your NVR not record anything for a week while it rebuilds? or will you just say fuckit all and abandon the data on the raid once you have a single disk failure? If you ran a jbod and lost a disk, just pull it out and replace it.. only data on that disk was lost and your back online in mins.
 
nayr said:
raid is dead, just run a big jbod.. especially for surveillance video.
Click to expand...

Maybe for the cheap Chinese toys, but RAID is very much alive and well in real recording systems.
It takes ~10 hours to rebuild an array comprised of 6TB drives if they are idle, and around 15 hours while they are recording depending on workload and how well the software schedules the writes. I don't spec RAID5 anymore, drives are big enough now that the extended rebuild time does really warrant RAID6.

I understand that most people here don't care about the security of their footage, but to state "raid is dead" is fairly inaccurate sweeping statement. Plenty of people *do* care about footage and some have regulatory requirements for retention.
 
Brad_C said:
but to state "raid is dead" is fairly inaccurate sweeping statement. Plenty of people *do* care about footage and some have regulatory requirements for retention.
Click to expand...

http://bfy.tw/7fgZ

If you have regulatory requirements for retention your far better off with a redundant recorder, both technically and legally.
 
nayr said:
http://bfy.tw/7fgZ
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http://bfy.tw/7fgZ

Oh goody. Baseless google research. If you'd searched a bit further you'd find plenty of contrary evidence pointing out that the hysterical ranting about the death of RAID5 was/is based on both a misunderstanding of basic statistics *and* a URE figure quoted on manufacturers specification sheets that is poorly understood and often misapplied. In fact if you actually believed in the mathematics from the google searches you were pointing to, you'd see that the drives in your JBOD's should be developing and reallocating several bad sectors per year. I bet they don't though.

Sure, as drive sizes increase RAID controllers have had to get a bit better at handling errors, and drives need regular scrubbing to give you confidence in the underlying media, but it still works. Like I said, anything above about 2TB drives we spec RAID6, but it's still RAID and rumors of its death have been greatly exaggerated (probably to drive advertising revenue on page hits).

nayr said:
If you have regulatory requirements for retention your far better off with a redundant recorder, both technically and legally.
Click to expand...

Nice to say, and probably practical for little systems, but when you get into larger system sizes it becomes somewhat expensive to redundantly record multiple petabytes of footage, so like any mitigation we balance that risk against cost. RAID still works, from 3 1TB drives right up to somewhat larger system configurations.

I'll leave this here lest it develop into another pissing match. Suffice to say for every bit of google searching you can point to to profess that RAID is dead, I can point to plenty of real-world examples where it's being used daily and successfully (like systems from pretty much every CCTV vendor from Hikvision through to Avigilon).
 
3x 2MP Cameras needing 20x days of storage does not require raid in any stretch.. he can accomplish that easily with a single 6TB disk.. he has no reason to use raid5 on 3 disks.

You said your self you dont spec raid 5 anymore now that the drives are big enough, I have not deployed raid 5 in production in quite a while.. Ive lost several raid 5 arrays from failed rebuilds in my day, when everyone stops using it, its dead.. my 10TB NVR is the smallest storage device I've built in years.. personally havent seen any 1Tb disks in a long time, they have all been long replaced by now in my datacenters..

sorry for being so general as saying Raid was dead, it still has its uses but Raid5 has been in the ground long enough its corpse has stopped smelling.. and to trust a storage system from Hikvision to correctly maintain integrity on a very large array is quite foolish.. where to you schedule these regular scrubs and monitor the drives so you have confidence in the underlying media? Not from the UI..

Unless you have some legal requirement to maintain video footage, your best off letting that disk die, loosing anything that was one it and getting the recorder back online w/reduced capacity while your RMA the drive, or order a replacement and live with the data remaining on the other drives.. Hikvision wont even let you have a hotspare installed in standby.. for the vast majority of people NVR uptime trumps data integrity.. I could loose all 10Tb of my video today and it would not hurt me at all, had anything the least bit important happned in the last month I would have already archived the relivant video off to another system.
 
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