Choice of HDD/SSD and USB/MicroSD for Video Surveillance Systems

Not only the depth of the video archive depends on the choice of a storage device, but also the stability of the data storage process, so neglecting the correct selection can cause various problems. To avoid them, you can use the recommendations of technical experts from the TRASSIR Team.

First of all, we do not recommend to use the HDDs which are designed for Home/Office PCs - such drives are not designed for round-the-clock recording, but only for 8-9 hours a day. One should use HDDs specially designed for video surveillance systems or for server-type storages (RAID edition HDDs).

TRASSIR technical specialists have conducted tests of CCTV purposed HDDs, among them - Seagate Skyhawk, Western Digital Purple and Toshiba Surveillance series. We have prepared a list of specific hard drive models that we were testing in Trassir:

If you are planning to use HDD models not from the list, we have common recommendations of HDD characteristics:

• The volume of the drive must meet the technical requirements of the NVR. For example, some NVRs support drives with maximum capacity of 6 or 8 TB.
• MTBF (mean time between failures) >= 1 million hours for 2~6 TB drives // >= 2 million hours for >=8 TB drives and higher workload.
• Working load >= 180 TB/year for 2~6 TB drives  // >= 550 TB/Year for over 8 TB drives.
• TBF >= 500 P/E cycles at 24/7 recording.
• Spindle speed is not so critical, but 7200 rpm is preferable.
• S.M.A.R.T. technology support.
• Support of multi-thread recording technology, like AllFrame / AllFrame AI .
• SMR (magnetic tiled disk writing technology) is not recommended for high-load systems and Drives over 8 TB.
• 3.5" form-factor, as the mounting points in the most of NVRs are made for this format.

Other recommendations:

• Provide the cooling or heating in the place, where the recording device is installed, according to the min/max temperature characteristics of the drive.
• Install SSD instead of HDD in the recorders which are planned to be used in harsh conditions in terms of high vibrations, for example - in transport. However, note that video surveillance HDDs are capable of more write/erase cycles unlike SSDs, in other words, HDDs are better suited for continuous recording of large amounts of data.
• Vibrations also threaten to damage the drives in huge multidisk systems - for that consider HDDs with anti-vibration technologies such as RAFF (from WD) / AcuTrack (from ST) / RVS (from HGST)
• Do not order NVRs/DVRs with already installed HDDs.

Trassir Software recording technology has it's peculiarities to be taken into account:

• It is better to use multiple disks than a single one. Let's say instead of one for 4 TB, we recommend using two for 2 TB.
• The drive size difference should not be more than 2 times! 2 and 8 TB, for example. Firstly, not all the space will be used on the larger drive. Secondly, it will slow down the archive recording and viewing.
• If new drives are added to an already working system with an archive, you will not get an instant increase in statistics. The software needs time to recalculate how much the archive will last now. The most accurate value of the archive depth will be obtained after passing through 2 recording rings (recording ring = current archive depth).
• One should not transfer a disk with an archive from one Trassir server to another. The entire archive may become inaccessible. By the same logic, one should not record the archive from several servers in one folder on a network storage.
• In the Windows OS, the maximum number of physical disks is 25 (corresponds to the number of characters in the English alphabet, in total it is 26 - the system disk is not accounted, since the TRASSIR software does not record archive to it), and it is not recommended to use more than 30 disks in Trassir ( e.g. together with iSCSI).
• It is better to use the NTFS file system for recording the archive, since testing of the archive’s operation with other file systems has not been carried out.

We also give recommendations for MicroSD cards and USB flash drives used in cameras:

1. The volume and the type of the flash drive must meet the technical requirements of the surveillance camera. For example, the camera supports maximum capacity of 128 GB USB Flash Drive. Other camera can support maximum capacity of 256 GB MicroSD card. 
2. We recommend MicroSD cards from WD Purple series.
3. MicroSD Class should be not lower than 10 (it will provide up to 10 MB/s read/write speed).
4. 3D NAND production technology of MicroSD cards.
5. Working load of MicroSD cards not less than 32 TB/year.
6. USB flash drive version - 2.0
7. For cameras with maximum bitrate of 8000 kbit/s, USB's read speed should be not lower than 4 MB/s and write speed not lower than 8 MB/s.
8. For cameras with maximum bitrate of 16000 kbit/s, USB's read speed should be not lower than 8 MB/s and write speed not lower than 16 MB/s.

Trassir Server Software provides the possibility to merge the archive from the camera to the recording Trassir Server in case of, for example, network loss between them. To be able to do that, the camera has to be natively integrated into Trassir, and "Remote storage" parameter has to be available:

Lists of natively integrated cameras

Vasily Selivantsev