Good morning,

 

Im new to unraid and i just finished building my first machine.

I have a question on the cache size and how many disks.

My motherboard has 2 NVME slots but I'm currently only using 1 due to 1 being shared with sata 1,

 

Current Setups

2x 14TB Seagate Exos

4x 6TB Iron Wolf Pro

1x 512 GB NVMe SSD

 

My main use of this server is primary PLEX server and Torrent Downloads

A few forums i have read say to use primary storage as cache and have it move the download to array after complete.

My questing is what king of life can i expect from these nvmes if I'm writing hundreds of gigabytes to it and than having it moved to the array.

 

I have also currently setup MakeMKV so I'm ripping movies directly from the server.

I do have 2x2TB WD Black NVME drives laying around, Should i upgrade my cache drive with one of these?

If i should upgrade it should i just upgrade the one i have installed? or get a dual PCIe adapter and install both?

 

Thank you for your help

Edited March 15, 20251 yr by ggonxhi
Spelling

31 minutes ago, ggonxhi said:

dual PCIe adapter

Typically those will require a SATA port for one of the drives. There are some that don't, but will only work if your motherboard can split the slot (bifurcation).

I can’t really help with your question about the nvme’s, not a hardware guy, but wanted to point out that it isn’t really necessary to use a cache drive when downloading torrents. I just download the torrents to a parity protected share and then transfer the completed downloads to another share. Typically the download speeds aren’t high enough to need the extra speed that I would get by downloading to an nvme cache drive. Even if they are slowed a little the process is all being done in the background so I wouldn’t ever notice the delay.

 

I think a high speed cache would be useful in any situation where you are actually waiting for transfers to complete. Not sure that Plex and an *arrs stack is one of those situations though.

I agree with @wgstarks on this one. I personally use "/mnt/user0/data" to purposefully bypass cache while still using the full array.

 

Quote

My questing is what king of life can i expect from these nvmes if I'm writing hundreds of gigabytes to it and than having it moved to the array.

 

Let me put it this way, my old  250GB 2.5" SATA SSD has over 400TB written to it and its still healthy.

Edited March 15, 20251 yr by MowMdown

Thank you for the help.

 

I actually had a single nvme adapter around and used that instead.

So now one of them is on the adapter and one on the motherboard m.2

It seems to work fine,  Any way to look if its using x4?

 

Thank you 

Type in to the terminal:  lspci -vvvv

 

You will get a long output, find the controller and look for the link state. For example of my JB585 Controller the "LnkSta: Speed 8GT/s, Width x2" is running in 2X mode.

 

Note that some PCIe devices like GPUs will change their link speed depending on load, not sure things like SATA controllers or HBAs can do that but I know GPUs will switch to 1X mode when not under load.

 

04:00.0 SATA controller: JMicron Technology Corp. JMB58x AHCI SATA controller (prog-if 01 [AHCI 1.0])
        Subsystem: JMicron Technology Corp. Device 0000
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 61
        IOMMU group: 12
        Region 0: I/O ports at f200 [size=128]
        Region 1: I/O ports at f180 [size=128]
        Region 2: I/O ports at f100 [size=128]
        Region 3: I/O ports at f080 [size=128]
        Region 4: I/O ports at f000 [size=128]
        Region 5: Memory at fc810000 (32-bit, non-prefetchable) [size=8K]
        Expansion ROM at fc800000 [disabled] [size=64K]
        Capabilities: [80] Power Management version 3
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot+,D3cold-)
                Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [90] MSI: Enable+ Count=8/8 Maskable- 64bit+
                Address: 00000000fee00000  Data: 0000
        Capabilities: [c0] Express (v2) Legacy Endpoint, IntMsgNum 0
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <1us, L1 <1us
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ TEE-IO-
                DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 128 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
                LnkCap: Port #0, Speed 8GT/s, Width x2, ASPM not supported
                        ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM Disabled; RCB 64 bytes, LnkDisable- CommClk-
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 8GT/s, Width x2 <------------------------------------------------- This parameter right here
                        TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt-