replication task; relevance of ECC Ram and sync. writes

[John Doe]

Hi Folks,

my current backup server got moved to a friends house. He claims my backup server draws too much power.
so I am looking for options to reduce power consumption now and I have an idea. may I ask you for your feedback?


as was situation:
ESXi with Truenas and PFsense for wireguard
-> about 60-80w

as is situation:
Truenas with wireguard
-> about 50w

may be situation:
get rid of the old server grade hardware and get low budget, low power consumption hardware.

I use ECC ram to have that error correction in place, both on the production system as well as on the backup system, since data is mission critical.
So I wonder in case of only replication task receiver, does the ECC Ram even matter?

Since the replication task will only transmit recursive backups every day, I have 24hrs to complete.
-> the transmit can be slow.
In case above Q is yes, can I enable sync writes directly to HDD to get rid of ECC Ram requirement?

Specs of Backup server in signature.

 

[unseen]

Hi Folks,

my current backup server got moved to a friends house. He claims my backup server draws too much power.
so I am looking for options to reduce power consumption now and I have an idea. may I ask you for your feedback?

If your backup server is drawing 50W and it is on for 24 hours per day, 365.25 days per year, it will use 438.3KW hours per year. Even at the worst possible final price for electricity (in Denmark), 438.3KWh costs about 200 Euro, or about 16.5 Euro per month. Maybe you could just give your friend 20 Euro per month for his electricity? (Or whatever your local currency is.)

...snip...

I use ECC ram to have that error correction in place, both on the production system as well as on the backup system, since data is mission critical.

So I wonder in case of only replication task receiver, does the ECC Ram even matter?

Since the replication task will only transmit recursive backups every day, I have 24hrs to complete.
-> the transmit can be slow.

I don't see how removing ECC would change anything here. Swapping it for standard DRAM would change the power consumption by such a small amount you would not be able to measure it.

Not using ECC DRAM, regardless of how data is written to disk, would only make your backup server less reliable - the same with using "low budget, low power consumption hardware" - and you have already said that the "data is mission critical". Even if you downsize the hardware to use a super low power motherboard and CPU (which most likely won't support ECC), the vast majority of the backup system's power consumption is going to be coming from the five 10TB WD Red drives. These consume 4.6W each at idle and 8.4W each while reading and writing.

In case above Q is yes, can I enable sync writes directly to HDD to get rid of ECC Ram requirement?

ECC DRAM protects against the data that you have just received from the other server being corrupted while it is stored in memory. Regardless of how data is written to disk, it will always spend some time in memory after being received from the network and before being written to disk. If data is "mission critical", skipping ECC DRAM only serves to increase your risk profile.

To my mind, having a dependable, private and offsite backup for 20 Euro per month is a great deal!

 

[somethingweird]

my current backup server got moved to a friends house. He claims my backup server draws too much power.

Is it a wiring issue or electric bill? (If electric bill - help pay the bill. if wiring issue - help pay for the wiring upgrade). Otherwise move to another friends house that has solar panels?

 

[Ericloewe]

So I wonder in case of only replication task receiver, does the ECC Ram even matter?

Yes it does, just as much as on the source.

In case above Q is yes, can I enable sync writes directly to HDD to get rid of ECC Ram requirement?

That doesn't make any sense, if anything sync writes would be less energy-efficient. If you mean "magically move my data from the network onto disk", that is quite literally impossible. Optimistically, it'll need to go through at least three buffers before it ends up on any sort of non-volatile storage (NIC's receive buffer, system memory to be checked for validity, disk buffer).

Your easiest avenue for lowering the power consumption is getting rid of the HBA, which means getting rid of the TrueNAS VM, which you can do by getting rid of the pfSense VM. You don't need pfSense just to run a site-to-site VPN. That's ~7 W just from the HBA, plus a bit more from marginal gains from not running a hypervisor and a whole second OS.

 

[Davvo]

Additionally you can spindown your drives since this is a replication target: a single spinup every day or week will not degrade them in any meaningful way imho.

HDD Spindown Timer 2.2.0

This resource was originally created by user: ngandrass on the TrueNAS Community Forums Archive. Please DM this account or comment in this thread to claim it. Disk spindown has always been an issue for various TrueNAS / FreeNAS users. This script utilizes iostat to detect I/O operations (reads...

www.truenas.com

 

[NickF]

This is generally old information, but this appears to be created by one of the primary ZFS developers at iXsystems

TuningPowerConsumption - FreeBSD Wiki

Perhaps some CPU frequency tuning will be impactful, tho I do not know the relevance of these tunables in FreeBSD 13

 

[John Doe]

oooops we might go in a wrong direction.

in case I could get rid of ECC ram by directly writing to disk, I could remove the supermicro board and get something with less onboard stuff which hopefully consumes less power (for electricity bill)

so in case I activate direct sync writes, will it make a difference to have ECC ram or not?
The purpose of this unit is only to receive snapshots from the other end, which of course has ECC memory and energy cost does not matter.



PS: in the meantime I could reduce the consumption to 27w in idle
4 fans, that old supermicro board, 1 ECC 8gb Ram module, no ESXi, no HBA, just the board, onboard nic 7x spinning rust (with spin down)

So above Q is now not really relevant for my plan anymore but I would like to know

Does ECC ram matter for direct sync writes and only receiving snapshots?

 

[Patrick M. Hausen]

All writes will go through the memory - how do you think they could happen otherwise?

Packets arrive on network interface, interrupt is triggered, network packet is parsed, payload is copied into a buffer in memory. That buffer will eventually be written to disk.

 

[WI_Hedgehog]

All writes will go through the memory - how do you think they could happen otherwise?

Packets arrive on network interface, interrupt is triggered, network packet is parsed, payload is copied into a buffer in memory. That buffer will eventually be written to disk.

There's now a networking strategy that goes from RAM to Ethernet to RAM in the other system, but to/from RAM it still needs to be handled somehow, along with permissions, locking, and such. (RDMA)