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SSD for caching question

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nikkon

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Dec 16, 2012
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57
Hi all,

I'm about to build a new system using the following:
- Asrock C2750D4I
- 16 GB ECC
- 4x 4TB WD-Red - new disks
- 4x 2TB Seagate - old nas disks
- u-nas 8bay case
- caching SSD?

My question is: For the Caching SSD do I need more than 120GB? IF not what are the suggestions in terms of speed?
Does it make sense to add more RAM?

Thx
 

Spearfoot

He of the long foot
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May 13, 2015
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2,084
Hi all,

I'm about to build a new system using the following:
- Asrock C2750D4I
- 16 GB ECC
- 4x 4TB WD-Red - new disks
- 4x 2TB Seagate - old nas disks
- u-nas 8bay case
- caching SSD?

My question is: For the Caching SSD do I need more than 120GB? IF not what are the suggestions in terms of speed?
Does it make sense to add more RAM?

Thx
You don't need an L2ARC device, because you haven't maxed out the RAM on your system yet. :smile:

The general rule-of-thumb is to first add all the RAM your system will support (64GB in your case) and only then - if you experience low hit ratios - think about adding an L2ARC device with a capacity roughly 2-4 times your installed RAM.

TL;DR - You'll be much better served buying more RAM.
 

joeschmuck

Old Man
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Don't do a SSD Cache without fully understanding what it really does and your use case.

What is your FreeNAS going to be used for?

If the answer is to access the same files over and over and day after day, of instance you are in an office have three heavy use databases that you and others access frequently. Then yes a Cache would help you.

If the answer is you are building a media library and a place to store photos and some backups, then a cache is not for you.

Additionally you should have typically 64GB or more of RAM before adding a cache. Odds are you will marginally slow your system down if you add a cache with 16GB RAM.

I also don't think you have been doing much reading in the forums yet because the motherboard you selected may have a premature death. ASRock has a firmware issue with some boards and I think this is one of them. Do a Google search on this board for failures.

The motherboard also isn't a fast system. Don't get me wrong, it's not bad but fast isn't a word I'd associate with it.

You need to specify your use case and then purchase a product which can at least meet those needs.

With all that said, if the motherboard was not prone to failure, the rest of your hardware, minus the cache, would be fine for a typical home NAS. I would add in a single small SSD to be the boot device vice using a USB Flash Drive.

Please do a bit more reading the forums and the "Resources" tab at the top of the forums section, this will help you choose the required hardware.
 

nikkon

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Dec 16, 2012
Messages
57
Hi,
It was a good decision to write and ask. Thank you for answering.
I saw the mobo discussion and I have thought it's an isolated case.
In terms of mobo, i would like to find something 17x17.
The purpose of the system is this one:
1. bkp's + photo and tons of movies
2. plex server
3. ISCSI for my ESXi/OpenStack other servers

No idea yet how much I need in terms of CPU power.
 

Spearfoot

He of the long foot
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Hi,
It was a good decision to write and ask. Thank you for answering.
I saw the mobo discussion and I have thought it's an isolated case.
In terms of mobo, i would like to find something 17x17.
The purpose of the system is this one:
1. bkp's + photo and tons of movies
2. plex server
3. ISCSI for my ESXi/OpenStack other servers

No idea yet how much I need in terms of CPU power.
For iSCSI you will want at "least 32GB of RAM if good performance is a requirement".
 

joeschmuck

Old Man
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Of all the items you listed, iSCSI is the only thing that concerns me. I have seen several conversations where a minimum RAM amount is 32GB. And I have no idea how CPU intensive it is, might be minimal.

Plex transcoding is likely the one item which will need some CPU horsepower. If you are planning to use BlueRay rips then you may need some good horsepower. If you plan to stream two or more movies at the same time then you will need a better CPU.

The motherboard you selected is 6.7" x 6.7", very small. My motherboard is 9.6" x 9.6" and I consider it small. My case is not small because I have a lot of hard drives. But my system was not cheap either and I can do a lot more than stream movies. But you could buy a motherboard like mine and just use a less powerful CPU, 16GB RAM and be happy knowing you could expand it at a later date if you needed to.
 

nikkon

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Dec 16, 2012
Messages
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Thanks for the reply.
Yes, Supermicro is my only choice anyway. As for the pfsense build (c2758 + ECC), supermicro will be the Mobo for sure.
Need to decide the CPU/socket because I need this to be kinda low consumption and quite(maybe Noctua on the case + some special CPU cooler).
P.S sry I never had the time to read the forum well. My questions could sound stupid :(
 

joeschmuck

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As for quiet... My system is whisper quiet and I'm not kidding. I'm into the ultra silence kick for all my computers. I use the stock CPU heatsink and fan, and then a few 120mm case fans running in slow speed (+7VDC) which gives me just enough air flow over the hard drives and forces air out the case to keep things cool.

Now I'm hoping my hard drives last long enough that I could buy a few SSDs to replace them for a marginal increase in cost. I'm only needing 7TB of storage capacity, maybe a pair of 8TB SSDs would be nice and then I could move everything into a very small enclosure and be ultra silent. A passive CPU heatsink would be in the plans as well. Hey, we can dream.

As for your CPU, I'd try to pick something fairly current as they use less power by design. The trade-off is of course price but if you want a silent system, you need something which would refrain from spinning up the CPU fan.

So I'd stick with a stock CPU fan for now and if you find out that it's too loud for you, only then would I recommend a heatsink change, but the hard drives are likely to be louder. If you mirrored my system (motherboard, CPU, and 1 stick of 16GB RAM), you would be set for a long time. Actually I (and I do mean myself) would buy a different motherboard if I could, the X11SSM-CTF just because of the additional SAS3 controller and 10GBASE-T ports and I want to tinker more with the hardware. But I've made my bed so I'll be fine.
 

joeschmuck

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tvsjr

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If you want decent performance, you also need your VM datastore on a pool of striped mirrors with a SLOG.
 

joeschmuck

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If you want decent performance, you also need your VM datastore on a pool of striped mirrors with a SLOG.
I guess it depends on what you consider decent performance. With my system I get well over 400MB/sec throughput on iSCSI and I'm running what would be considered a slow pool configuration. My Windows VMs fly so long as they are on the same physical machine. If you are using an external interface then of course things will crawl. I don't run an SLOG but that doesn't mean I'm doing things right either.
 

tvsjr

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I guess it depends on what you consider decent performance. With my system I get well over 400MB/sec throughput on iSCSI and I'm running what would be considered a slow pool configuration. My Windows VMs fly so long as they are on the same physical machine. If you are using an external interface then of course things will crawl. I don't run an SLOG but that doesn't mean I'm doing things right either.
I should correct myself and say you'll see very limited IOPS performance. Bulk reads and writes are fairly trivial... it's all the little reads and writes that kill you. One or two vdevs of 5400/5900RPM drives isn't going to deliver stellar performance when multiple VMs are demanding lots of IO. I assume you're also not forcing sync writes (and living with the risk)?
 

joeschmuck

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I assume you're also not forcing sync writes (and living with the risk)?
Heck, I have no idea. I was just happy to get iSCSI working a few months ago and it works great. I only use it for testing something out, it's not any VMs that I care about.
 

tvsjr

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Is E3-1240L/60L v5 enought for plex server ? (max 3 clients)
For 1080p, I believe so. For 4K, I believe you may run into limitations. I haven't done it myself, however.
 

joeschmuck

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Is E3-1240L/60L v5 enought for plex server ? (max 3 clients)
Ouch, you know the reason it's a low powered unit is because it's underclocked. My E3-1230 V5 runs are 3.4 GHz while the E3-1240L runs at 2.1 GHz, that is a big difference. Price wise the E3-1230 V5 or even the E3-1240 is cheaper than the "L" version.

Okay, so I've done a little quick research and it appears that the "L" version will jump into high speed for single threaded operations and even add a little boost for four cores. If you disabled the HT for the CPU then you could reap the full benefits it looks like.

One additional thought is you might be looking at this perticular CPU due to TDP. Remember that TDP is for when the CPU is running at 100% which is far from true for normal FreeNAS operation. Most of the time it's sitting idle. As for if the "L" CPU will handle Plex, absolutely. I can't tell you if it will do three streams at HD (1080p) levels though. Three streams typically requires a lot of CPU horsepower. The way to get around this is to set your quality level appropriately. I myself would not buy an "L" CPU if I were planning to stream 3 Plex transcoded streams at the same time and that is only due to my ignorance. Sorry, wish I had some definative answer. If I had a third Plex player then I could run it on my end to see how things work but I only have two Roku 3's.
 

nikkon

Member
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Dec 16, 2012
Messages
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Ok, it makes a lot of sense. will go then for the higher versions without the L.
probably 1230 or 1270 v5.
 

Stux

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1230 is the best bang for buck for a quad core + HT CPU.
 
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