ZeusRAM Expected Performance?

coolrunnings82

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Mar 26, 2012
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I recently purchased a ZeusRAM Z4RZF3D-8UC for use as a ZIL on my storage server now that I'm planning to switch to iSCSI. I put it in my 4 drive pair of mirrors lab test box. I ran benchmarks and didn't get nearly the 4k results I expected. I pulled the drive and put it in one of my R710's for testing. I was using a Dell PERC H200 SAS controller (crossflashed to a 9211-8i) with a 4 port breakout cable in both the lab test box and my R710. Here are the benchmark results obtained on the Windows server:

-----------------------------------------------------------------------
CrystalDiskMark 5.1.2 x64 (C) 2007-2016 hiyohiyo
Crystal Dew World : Crystal Dew World
-----------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

Sequential Read (Q= 32,T= 1) : 499.837 MB/s
Sequential Write (Q= 32,T= 1) : 448.735 MB/s
Random Read 4KiB (Q= 32,T= 1) : 242.902 MB/s [ 59302.2 IOPS]
Random Write 4KiB (Q= 32,T= 1) : 204.272 MB/s [ 49871.1 IOPS]
Sequential Read (T= 1) : 449.006 MB/s
Sequential Write (T= 1) : 419.027 MB/s
Random Read 4KiB (Q= 1,T= 1) : 53.130 MB/s [ 12971.2 IOPS]
Random Write 4KiB (Q= 1,T= 1) : 47.684 MB/s [ 11641.6 IOPS]

Test : 100 MiB [E: 0.5% (36.0/7627.0 MiB)] (x1) [Interval=5 sec]
Date : 2016/09/09 21:04:55
OS : Windows Server 2012 R2 [6.3 Build 9600] (x64)


Those results don't look remotely like what I anticipated seeing on 4k writes. According to the spec sheets, it should be capable of the following specs:
Performance
Latency Average (ms)
<23µs /<23µs
Read Throughput (max MB/s, sequential 64k)
900/475
Write Throughput (max MB/s, sequential 64K)
800/430
Read IOPS (max IOPS, random 4k)
100,000/69,000
Write IOPS (max IOPS, random 4k)
100,000/51,000

Do you guys think this is due to controller or cables perhaps? If not, any ideas? The drive was listed as new when I purchased it...
 

gea

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Dec 31, 2010
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According to the specs https://www.hgst.com/sites/default/files/resources/HGST_ZeusRAM_ds.pdf the faster values are for a dual port SAS mpio maybe with two SAS controller configuration. I suppose you use a single port/ single controller setup.

In this case your values (49k/59k iops, qd32) and 419/449 MB/s sequential are very good and nearly as advertised. The qd1 values are lower but the best performance is always given with higher queue depths (for a ZIL qd1 values would be more relevant). The exact values may be only achievable in a special test scenario at HGST.

You may use a 3008 HBA or check for newest LSI firmware that may improve the values a little but they are really ok.

btw
ZeusRAM was the fastest ZIL for years.
In the meantime NVMe can be a faster and cheaper option.
 

T_Minus

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Just to be clear @coolrunnings82 those #s are not of a pool with the ZeusRam as a SLOG device, correct? But instead just the device 'tested' in Windows?
 

coolrunnings82

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Yes, that's correct. Thinking I'll probably sell it since I don't anticipate any dual-ported storage systems any time soon.
 

T_Minus

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T_Minus

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azev

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yeah they are super pricey for SAS cable, but they used to be more expansive in the past. I think a year ago or so I bought used on ebay for 50 buks.

Someone should organized group buy and it can be had for $38 each :)

This cable would be perfect for desktop setup with dual port sas SSD.
 

fractal

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Jun 7, 2016
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Criminies.

I bought a couple 6g HBAs ( Dell PowerEdge H310 Perc Adapter 8-Port 6Gb/s SAS RAID Controller 0HV52W 0T3F4V ) that came with a SFF to SAS cable for less than you are showing here. Both the card and the cable are Dell labeled and are only listed at 6G. I don't know if they work at 12G since I don't have any 12G drives or HBAs, but they don't look any different than the ones you are showing for 80 bucks.

The H310 is the newer version of the OP's H200 so I would think that a 6G cable would be fine.
 

T_Minus

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I'm pretty sure those are not dual port capable cables, but maybe I'm wrong ?? I have a couple of those someplace too.
 

Rand__

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Mar 6, 2014
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I'm pretty sure those are not dual port capable cables, but maybe I'm wrong ?? I have a couple of those someplace too.
Have you ever found out whether those were dual port capable cables?;)

We are talking about these, right?
 

T_Minus

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@Rand__ you made me raelize I haven't even tested the EXPENSIVE real dual-port cables I purchased for the Zeus. After those cahssis arrived really beat up I havent put in the effort to get the build done, and htem tested. It's on the books to get done just not a top priority at the moment.