Member Discussion

OS & VMS On SSD Or Everything On Single RAID Array

I'm looking at setting up a Dell r520 with a RAID array, running Luxriot. Any best practices surrounding what goes where? Is OK to put everything on one volume? Should I put the OS & VMS on an SSD and the storage on the array? Does it matter?

I sent an email to Luxriot about this but no response yet.

In general, I think you are better off putting the OS & VMS on an SSD.

Here is the trick with the 520, get a decent raid card such as the Perc H710p, and create a virtual disk for the video storage, don't do the raid through windows. With a virtual disk you can actually add more drives to the array later on, then expand the size in windows if that makes sense. But if you have more than 1 VD on the array, you can't expand it (limitation of the Raid controller) so do a Raid for video storage, then you can actually use the IDRAC Enterprise and install the OS and VMS on a flash drive, giving you nothing but pure storage on the RAID. The one problem from dell is that they will create a VD for every drive in the array, first thing you do is when you power on the system is blow out all the virtual disks and create 1 VD for storage.

So that should leave you with 2 SSD's in a RAID1, then you have 6 drives available for RAID, which should give you plenty of storage. You can get really creative with the dells, I used them a ton for larger sized jobs.

We have been using RAID 1 sets with SSD drives for the OS and then JBODs with Seagate SV35 drives for the video storage. I don't think the added speed/cost of SSD will come into play with video storage. SSD drives are too small at this point to be used for larger storage needs IMO. Now, if this was a situation where speed WAS in fact needed and the budget allowed it, SSD may be more logical. But, again IMO, video storage is about slow and steady writes/reads and that is the wheelhouse of platter drives like the SV35 and WD Purple lines.

As far as reliability, I think SSD is getting close to platter drives as far as MTBF. I know the Intel enterprise SSD drives are rated at 10 writes per day for 5 years. To me that is about what I hope a platter drive will deliver as well, 5 years.

Regarding SSD reliability, here's a pretty good article comparing enterprise SSD's to high-end consumer SSD's.

Tweaktown Consumer vs. Enterprise SSD Comparison

Response from Luxriot:

"Yes it is good to have OS and VMS on a separate SSD. The data can be on a raid array either raid 5 or raid 6 with a hot spare.

This is the best practice and this is how we build our Luxriot Servers.

If you would like additional redundancy for O.S and VMS you can create a separate raid 1 array on 2 SSDs."

Just make sure if there are a lot of VMS log files theyre not being saved on the SSD...

Using SSD for your OS, and put VMS video storage on separate HDD RAID array.

1. Cost: SSD still cost too much comparing to HDD.

2. System responsiveness: Mixing OS and video on SSD reduces system responsiveness. The reason you want SSD is for system performance (not video performance).

3. Lifetime: Limited SSD writing cycles is not really for applications like video surveillance, which is writing mostly.

4. Performance: You don't gain too much from video performance prospective as regular HDD array is more than capable of handling IO load.

5. System Reliability: Continuous writing on C: drive will pretty much make C: drive NTFS file system corruptions when there is an unexpected system shutdown.

As a matter of fact, we will issue a warning ticket if the user configured to record on OS C: drive for our customers. We typically see this when customers replaced their cameras and forgot changing the recording path.

Put a Heavy workstation with redundant power.

forget about RAID in this "server".
Work with OS and VMS on a single SSD and use a NAS as a storage.

You can work with a excelent performance, in a good price and with scalability os storage.

I would never recommend putting the O/S and programs on a data RAID array, nor would I recommend recording on the O/S drive. There are a number of potential problems:

  1. If the O/S is on the recording drives, any problems with the O/S that would require wiping the drive (and there are many) will also require wiping the video recordings.
  2. In many cases, systems cannot boot from the data (RAID) drives.
  3. Each type of storage should be optimized for its use: O/S drives are typically read often and written to lightly whereas video storage drives are typically written to continuously and read from occasionally. Mixing the two functions on one storage system is far from optimal.