Please vet this new build

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T75

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Hello, I've owned a hand built equivalent of a FreeNAS mini (but with a D-1540 based SuperMicro board) that I ended up gravitating to after a lot of parts purchasing as I tried to decide what I really wanted. I've been very pleased with it, though getting some of the plugins to work has been, at times, frustrating.

Lately, I've been thinking of building a second machine using parts that I've accumulated over the past couple of years. This is what I have to work with:

Chassis: Supermicro CSE-823TQ-653PLB
CPU: Intel Xeon E3-1276 V3
Mainboard: Supermicro X10SL7-F
RAID Controller: LSI 9211-8i (PCIe 3.0 x8)
Drives: 6x3TB WD Red and 8x512GB Samsung 850 Pro
2.5" bay: IcyDock MB998IP-B 8 bay cage
SLOG: Intel DC S3500 120GB
Boot drive: Intel 535 120GB
AOC NIC: Supermicro AOC-SG-I2 2x1GBe NIC (PCIe 2.o x4)
RAM: 4xCrucial 8GB DDR3-1600 ECC CT4484978

The six 3TB drives will be in a raidz2 and the SSDs will be a raid 10/100 (still up in the air). Boot drive and SLOG will live in the CDROM and floppy drive section of the chassis.

Besides the silly factor of having all of these items live in one case, does anything raise a red flag?

TIA,
T

Edit: Adding the RAM would be nice.
 

m0nkey_

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Your hardware appears to pass the giggle test. :smile:

Just one thing; Any reason to have a SLOG device? Are you planning on doing lots of synchronous writes?
 

T75

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Thanks for checking.

To answer your question, virtually every desktop and laptop that will connect to it has a SSD in it, and I noticed that after adding the SLOG in my other server, multi-GB transfers from these clients finished faster. Since the raidz and the raid 10/100 will be used for different zpools, the SLOG is intended to help out the 6x3TB raidz zpool.
 

m0nkey_

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To answer your question, virtually every desktop and laptop that will connect to it has a SSD in it, and I noticed that after adding the SLOG in my other server, multi-GB transfers from these clients finished faster. Since the raidz and the raid 10/100 will be used for different zpools, the SLOG is intended to help out the 6x3TB raidz zpool.
It may appear that way, however writing files over SMB or AFP wont have any noticeable impact on writes, since they go over as asynchronous and the SLOG device will be under utilized. That 6 drive pool will easily saturate a gigabit connection without a SLOG. Synchronous writes on the other hand, such as a ESXI NFS datastore where every write is synchronous, you will see a vast improvement in performance.
 

T75

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It's quite probable that my SLOG is vastly underutilized except for those few instances when I have multiple writes from several clients. However, in the meantime, what else would I use that S3500 for? ;)

As I understand it, if I need to pull that SLOG drive out for some other purpose, the rest of the system will still function perfectly fine without it. I don't plan to add any new servers this year as I have all this extra hardware laying around. I've never considered VMWare products because it's my understanding that all the good bits are reserved for their licensed versions.

Could you explain why the SLOG might impact the pool's ability to write out to a 1GBe connection? I'm not sure I understand what you mean. I thought that would be affected by ARC or L2ARC, no?
 

m0nkey_

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There are plenty of threads on the forum relating to the pro's and con's of both a SLOG and L2ARC. But it basically comes down to two key points:
  • SLOG: Separate intent LOG. Using FreeNAS as a ESXi/Xen or other storage datastore. Maybe some database applications too. More details on what a SLOG does, check this post: https://forums.freenas.org/index.php?threads/some-insights-into-slog-zil-with-zfs-on-freenas.13633/
  • L2ARC: When the ARC gets full, it pushes what is in RAM to the L2ARC device. This can be a bad thing for low memory systems, so it's always better to throw more RAM in the box than to add a L2ARC. If your ARC hit rate is low, add more RAM before adding a L2ARC device.
I suggest checking out this thread by @cyberjock: https://forums.freenas.org/index.ph...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/
 

T75

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That 6 drive pool will easily saturate a gigabit connection without a SLOG.

I'm not sure you read my question entirely. I don't understand how a SLOG device would impact READs from a zpool.

As for ARC, I have the maximum amount of RAM that a Xeon E3 class processor (and main board) can address.
 

Stux

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I'm not sure you read my question entirely. I don't understand how a SLOG device would impact READs from a zpool.

As for ARC, I have the maximum amount of RAM that a Xeon E3 class processor (and main board) can address.

The maximum ram that a Haswell board can address ;)

Skylake supports 64GB.

A SLOG should not affect reads. A SLOG is only ever read from when mounting the pool AFTER you crash. Its purpose is to act as a location to immediately redirect synchronous writes to, without having to immediatelty write the synchronous writes to the main pool. The data which was written to the SLOG will then get flushed to the main pool in the next transaction group.

If you're not using iSCSI or NFS, you probably don't need a SLOG. But as far as I know, if its a good SLOG drive (like the Intel drives are) then it shouldn't hurt, at least on a disk based system. Your SSD pool would probably be faster without it :)

PS: I know this is a necro.
 
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