HDD versus SSD

[imnoboist]

Hello!

I'm working on spec'ing out a server and I'm a bit torn on HDD versus SSD. I could have somewhere around 30 cameras, many of which will be recording in 1080p using at least 15 FPS if not more. Can HDD's in a RAID 6 array keep up with a dozen or so cameras all recording 1080p @ 15 FPS simultaneously? Or should I go with SSDs?

Thanks for the advice!

-Sean

[diluted]

It all depends on your raid 6 setup - are you running a physical controller, how much cache on the controller, how many hard drives, what speed etc etc.. ? Have you tried to run any IOP benchmarks across your array?

I'm up to 12 HD cameras without issue on my server but it's pretty beefy, and runs other VMs as well.

Try running these commands and post the output

"sudo hdparm -v /dev/sda"

mine reports the following:

/dev/sda:
Timing cached reads: 13204 MB in 2.00 seconds = 6607.15 MB/sec
Timing buffered disk reads: 568 MB in 3.01 seconds = 188.71 MB/sec

also try

"dd if=/dev/zero of=/tmp/output bs=8k count=10k; rm -f /tmp/output"

which gives me:

10240+0 records in
10240+0 records out
83886080 bytes (84 MB) copied, 0.0731401 s, 1.1 GB/s


*edit*
Also if raid 6 turns out to be too slow (which it shouldn't) you can always go raid 10

[thomas1977]

Hi Sean,
is your server ready and running. Can you give some technical details. I need a new server for a similar environment and am still looking for hardware requirements.

Thanks for the advice!
thomas

[niwotsmitty]

I'm in the process of building a Zoneminder server, so I asked myself the same questions. I decided to use an SSD for boot and the OS, but RAID-5 for the camera data. SSDs are great for read/write performance, but in a video capture system, if you want to use SSD, make sure you get very good quality ones that can survive high write throughput. Unfortunately, high-write SSDs aren't the cheap SSDs.

As for throughput on the RAID controllers, a good HW RAID controller (such as the LSI/Avago MegaRAID cards) can easily sustain HDD media rates for writes in RAID-5 or RAID-6.

I hope that helps!