Regarding the Synology, what is it doing?
Is it indexing? Depending on the actual contents of your library, Plexâs activity is based on the number of items indexed. It does not matter if movies, episodes, music, or photos, each item creates a metadata entry (bundle) and a set of records in the database.
I think there is a misunderstanding about how a NAS behaves when itâs used for concurrent read/write operations such as that which PMS does during normal operation versus reading or writing one file at a time over a network
When an application reads & writes locally , which is what PMS running on the NAS does, it is a lot faster than if youâre trying to do something over the network to it. The drives themselves are capable of approximately 100 iops (I/O per second). PMS, or any application, running on your NAS, is fully capable of driving them up to their I/O per second limit if it needed.
In contrast, directory operations (getting the list of files in a directory) are cached just as files are. Files are read ahead by your computer (where PMS is running) in large blocks .
Now add how RAID works. RAID works by distributing the data and the data protection parity over the otherwise Reduntant Array of Independent Disks (RAID).
When you write 1KB to a file, somewhere on that RAID, the parity must be updated.
Letâs assume a typical RAID âstripeâ (blocking) size of 64KB. This means that data is split up in 64KB blocks (Windows calls them clusters but the same thing). For each block written, regardless of size, the parity, which itself is distributed among all the drives, must be updated. If youâre updating a lot of files, thatâs a lot of parity locations to update and data to replicate.
The same happens when you read (almost). It reads all the blocks to satisfy the read request plus the parity. Why? It does this to verify data integrity. It uses the parity to make sure what it did read matches. If not, it figures it out and resolves the data corruption before giving it to you.
Where folks get in trouble is when they put drives in a NAS which arenât NAS-rated. Green drives or Desktop drives are NOT intended for this type of extended activity. Itâs why we pay more for NAS drives. They have more durable components and have been tested to verify they will not fail.
In the event they do, they have an additional feature in their firmware which desktop drives do not have.
They have Time Limited Error Recovery (TLER).
What does need to be defined here is:
- Is the drive tray rattling? (yes, they do love to rattle if the drives arenât locked down tight.)
- Is it the nature of that drive manufacturer to produce drives which are ânoisierâ than others. 7200 RPM drives make a lot more noise than 5400 RPM but do give you a big speed increase. Pick your poison.
- Last but by far least, is there enough memory in the NAS for all the applications to run without âswappingâ to disk? PMS will survive in 2GB, 4GB is more tolerable, 8GB is a sweet spot on Synology for those with hardware transcoding. QNAP is about the same. For both, once above 8GB, itâs based entirely on what other applications are running as services on the NAS concurrent with PMS
