Samsung PM853T SSD Review

Samsung PM853T SSD Review

Here at Teknophiles, we don’t believe in a once-size-fits-all approach to selecting hard drives for our lab servers. We prefer to adhere to the rule of specificity, where drives have a defined purpose and drive selection is based on several criteria that suit that purpose. In no particular order, we evaluate capacity, cost, reliability, performance and form factor when selecting a drive for a particular role.

Looking at this list of attributes, it’s easy to reach the conclusion that simply selecting the fastest drive would be a no-brainer for all applications. But fast drives come at an expense – both literal expense, as well as capacity expense. And, frankly, there are times where you just don’t need the the capacity or even the raw performance that some drives offer. One example, as detailed in our Silicon Power S60 60GB SSD Review, are server OS drives. On nearly every server we build, any serious workload is going to be performed on a dedicated array or SAN LUN, where IOPS and throughput are known quantities that are appropriately sized. As such, dedicated operating system drives typically experience low I/O and are approximately 75-80% read operation. You just won’t see much benefit by spending extra cash on a blazing fast SSD for your OS. And when you further consider that we nearly always configure our OS drives in RAID-1, even relatively “slow” SSDs will yield perfectly usable read speeds for a typical operating system. Heck, reliability even takes somewhat of a back seat when using cheaper drives in a RAID-1 configuration – by simply by keeping an extra $30 drive or two on hand as spares, you’ll still come out ahead financially, with no little down time waiting on a new drive to arrive.

Have Your Cake and Eat It Too

But what about those times where you do need speed, capacity, and reliability? It’s sorta like that old muscle car adage: cheap, fast, reliable – pick any two. The same premise generally holds true for computer components, including hard drives. Simply put, if you want fast and cheap, it likely won’t be reliable. Reliable and cheap? It’s not gonna be fast. You want all three? Unfortunately, you’re going to have to pay for it.

Or are you?

Perhaps there’s a happy medium – as long as you understand what it is you’re looking for. You see, performance is relative. There are certainly applications that require an abundance of IOPS. Others require significant write endurance. Others yet are heavily read biased. For each of these use cases, there are drives that fit the specific profile. For us, we needed some reliable, reasonably fast drives that will be 80% read-biased, but not break the bank. We’ve think we’ve found the sweet spot with the Samsung PM853T.

The Samsung PM853T

The Samsung PM853T series drives were mass produced around 2014-2016, so all the drives floating around out there are data center pulls, some with low hours, and in some cases, even New Old-Stock (NOS). Still, these are a great deal and can be had for as low as $0.10 per GB. Keep in mind that many of these drives are OEM drives that were sold bundled with servers, and thus will carry no warranty from the drive manufacturer even if they had a recent manufacture date. At this price point, however, having a cold-spare on hand is certainly achievable, and is highly recommended.

Samsung considers these drives to be a mixed workload drive with high sustained performance, which is perfect for our purposes. Note that the PM853T is an TLC SATA III 6 Gb/s drive, so like other SATA SSDs, it’s limited to a theoretical 600 MB/s. In our case, this is mostly irrelevant, however, as we’ll be using these in RAID-1/0 arrays as the disk subsystem for Hyper-V clusters. Given a minimum of 4 disks in an array (and possibly many more), this configuration can easily saturate the 2000 MB/s maximum throughput of a single 4-lane SFF-808x connector on an older SAS2 HBA like the LSI-Avago SAS 9210-8i.

Attributes

Samsung offered the PM853T in 240 / 480 / 960 GB sizes, and the drive offers many features not found on Samsung’s consumer drives.

Samsung PM853T – Specifications
Form factor 2.5 inches
Capacity 240 / 480 / 960 GB
Host Interface SATA3 – 6 Gb/s
Encryption AES 256-bit Hardware Encryption
Mean time 2.0 million hours
Uncorrectable bit 1 in 10^17
Power consumption Active Read/Write : 2.7 Watt/3.8 Watt, Idle : 1.2 Watt
TBW – 240 GB : 150 TBW
– 480 GB : 300 TBW
– 960 GB : 600 TBW
Cache power protection Supported
Sequential R/W (MB/s) Up to 530 / 420 MB/s
Random R/W (IOPs) Up to 90,000 / 14,000
Physical dimensions 100mm x 70mm x 7mm
Weight 63g

Among the features, Samsung lists the following:

    Consistent high-quality performance. Delivers consistent performance under diverse workloads to meet various data center demands.
    Advanced Error-Correcting Code (ECC) engine. Corrects read failures to greatly improve the reliability of the data stored in the memory for higher error correction and endurance than the BCH code can deliver alone.
    End-to-end protection. Extends error detection to cover the entire path, from the host interface to the NAND flash memory in the SSD for superior data integrity.
    Power-loss protection. Ensures no data loss during unexpected power failures by using the power supply of tantalum capacitors to borrow enough time to store all cached data to flash memory.
    SMART technology. Anticipates failures and warns users of impending drive failure, enabling time to replace the ailing drive to avoid data loss and system failure malfunctions.
    Thermal throttling. Regulates the temperature of the hardware components automatically to protect them from overheating by managing its performance level to prevent data loss.

Performance

So how does it perform? Samsung provides an enormous amount of data in their product brief on the PM853T, but here are some highlights of tests conducted in Samsung’s data lab using a PM853T 480 GB drive against a competitor’s product. Samsung uses the following tools to generate this data: Fio 2.1.3, Jetstress, and IOMeter.

Sustained Performance Tests

In this test, Samsung pitted the PM853T against an competitor’s MLC SSD drive during an 11 hour workload. The results indicate that the Samsung drive shows much lower latency with less standard deviation (more consistency). Overall the Samsung drive also had overall higher average IOPS.

Read/Write Tests

Additionally, the Samsung drive outperformed it’s competitor in both sustained random, as well as sequential read/write tests, achieving nearly 160000 IOPS at 100% random read in RAID-5 configurations, and 30000 IOPS at 100% random write in RAID-1 configurations.

In the sequential read tests throughput reached approximately 1500 MB/s in RAID-1 and over 1200 MB/s write in RAID-5 and outperforms its competitor as much as 29%, depending on RAID configuration and queue depth.

In mixed workloads it’s a similar story – the PM853T performs outperforms its competitor at all queue depths, in both non-RAID and RAID configurations, achieving more than 60,000 IOPs in RAID-1 at a RW ratio of 75:25, which is similar to typical virtual environment workloads.

Latency

In terms of average and maximum latency, the PM853T again performs admirably against a competitor.

Application Workloads

Finally, in both virtual environments using multiple VMs, as well in as various real-world application workloads, the PM853T again outperforms its competitor across the board.

In our own much simpler tests, we used a Samsung PM853T 960 GB drive. This drive was a server pull that, as you can see, had very low hours.

We saw read/write performance very much in line with Samsung’s official claims and consistently saw over sequential reads over 550 MB/s read and sequential writes over 420 MB/s.

Limitations

All this said, these drives do have certain limitations that should be at least touched upon:

    Form Factor. These drives are 2.5″, so they may not fit in your existing NAS, at least not without an adapter. Though at 7 mm z-height these will easily fit in all 2.5″ drive locations.
    SATA III. The PM853T is SATA III, not SAS or PCI-E, so if you need the raw performance of PCI-E or the expanded feature set of SAS such as multiple initiators, full duplex speeds or multipath I/O, then these drives are not for you.
    Write Speed. Being a read-biased drive, one would expect write performance to take a bit of a hit. These drives certainly do not display write speeds as fast as modern PCI-E/NVMe based drives. That said, they’re no slouch either, especially in RAID arrays. And at $0.10 per GB, you can actually afford to build an array with them.
    Endurance. Again, being a read-centric TLC SSD, the PM853T is only rated at 0.3 drive writes per day (DWPD). SLC drives can typically handle as many as 10x the number of write cycles that MLC or TLC drives can. This translates to nearly 300 GB in drive writes daily for 5 years. Unless you have some atypical use case, these drives should last a very long time in a typical 80%/20% R/W virtualization scenario.

Conclusion

So how exactly are we using these drives at Teknophiles? We’re currently running nearly 30 virtual machines on a single 1.8TB RAID-1/0 volume (4 x 960GB Samsung PM853T) and these drives don’t break a sweat. Even when hammering the environment with Windows Updates, mass live migrations or boot storms, these drives hold up well. The PM853T’s random IO performance and low latency makes it quite suitable to meet the demands of the mixed workloads that virtual machines place on the disk subsystem. Additionally, with numerous 853T drives currently in play (4 x 960 GB and 2 x 480 GB), we’ve not had a single failure in more than 10k hours use – these seem to be quite reliable drives. Simply put, for a home Hyper-V or ESX lab, it’s hard to imagine a better drive for the money. Factor in the quite excellent IO and throughput per watt of power consumption these drives produce, and you have a clear winner with the PM853T.

Taming the HP DL180 G5

Taming the HP DL180 G5

Introduction

The HP ProLiant DL180 G5 can be an excellent, inexpensive storage platform for the home or lab.  It uses tried and true HP hardware, accommodates dual Xeon CPUs plus 12 x 3.5″ drives in a 2RU chassis, and both server and backplane play nicely with the ubiquitous LSI HBAs in IT mode, should you choose to use Linux software RAID.  With well-equipped models going for under $300 shipped on ebay, it’s a solid foundation on which to build a file server or shared storage platform.  But there is one problem when using the DL180 outside of a datacenter environment – it’s loud.  Not quite 747-taking-off-loud once it idles down, but it’s still loud enough that my wife wants to know why she can hear one of my “wind machines” through the master bathroom floor vents.  Of course, here at Teknophiles, we’re not going to let a little thing like fan noise stop us from using what is otherwise a compelling platform, are we?  Nope.  With a few simple modifications, we’ll show you how to domesticate this unruly beast.

DL180 Cooling

This thing blows!
This thing blows!

The DL180 G5 employs four 60mm x 38mm Delta PFC0612DE-7Q1F PWM fans that serve double-duty as chassis and processor cooling fans.  Very capable fans, these Deltas churn out air at a rate of 68 CFM at a whopping 12000 RPM.  They also consume as much as 16.8 W (each!), and produce an unfriendly 65.5 dBA.  Not exactly ideal for a basement or lab situation in which you must share the work space.  Even at 50%, these fans spin at nearly 6000 RPM and produce a good bit of noise.

There’s some good news, however.  Unlike many servers, the HP DL180 uses standard 5-pin fan connectors to connect the PWM fans rather than a proprietary connector or a fan module.  This simply means that, since we only plan on running a single Xeon L5420 processor, we should be able to find a suitable replacement fan that’s lower RPM, and therefore much quieter, yet still offers decent enough air flow to keep the drives and CPU from overheating.  Conceptually, the server should ramp fan RPM based on CPU and various board temperatures, so even a slower fan should be able provide airflow above the Delta fan’s idle flow rate, should the additional cooling be needed.

These theories are all well and good, but the engineers at HP are some pretty smart folks.  Most enterprise chassis are quite good at monitoring hardware, including the cooling components.  Some servers might have a minimum fan speed threshold, below which the server may go into a “limp mode” (i.e. full fan power), or even fail to POST altogether.  So, before we shell out money for new fans, we need a proof of concept to demonstrate that the server will not balk at a slower RPM fan.

Fan Test

Like many dutiful IT guys, we have piles of abandoned computer crap in our basements.  This may make our wives nuts, but occasionally we get to smugly smile when some old part fits the bill perfectly for a “critical” test we’re performing.  Such was the case here, when an old AMD PWM processor fan was called into service for our DL180 G5 proof of concept.

Spinning is good.

 

With the test fan in place, the server was booted into the BIOS to check fan speeds.  As fate would have it, the HP DL180 G5 doesn’t appear to be phased that one of it’s fans is spinning at a mere fraction of it’s normal speed.  Here you can see the AMD CPU fan rotating at a modest 1776 RPM, while the stock fans spin at 5800 RPM.  You may also note that the lower critical (LC) value for fan RPM is 0.00.  As long as a fan is detected, the server should boot and operate as normal.  It’s on us, then, to monitor temps and make sure we don’t melt anything!

One of these is not like the others.
One of these is not like the others.

 

New Fan Installation

Now, on to the fun stuff.  After sampling a few different fans in the 60mm x 38mm form factor, we settled on a MagLev Sunon PWM fan.  Known for their quiet bearing operation and long life, The MagLev Sunon fans are some of our favorite fans for numerous applications.  We selected the PSD1206PMV3-A, which can often times be found under analogous Dell part numbers.  This fan flows just over 34 CFM, but only consumes 3.4 W, generating significant power savings when multiplied across four fans.  Best yet, it’s max rotational speed is around 8000 RPM, which should yield much lower sound levels at idle speeds.



It was evident upon receiving the new Sunons that this wasn’t going to be a plug-and-play affair, however.  As you can clearly see, the new fans use a non-standard 4-pin connector, and also have a quite short pigtail.  To make these fans work in the DL180, we’re going have to break out the soldering iron and the crimp tool.

De-pinning the connector

After cutting off the old 4-pin connector, appropriately colored wires were soldered onto the pigtail to extend the wires to the proper length.  This will allow to us the DL180 chassis’ cable management to keep things neatly tucked away inside the case.   One thing we do have to be careful of is the order of the pins in the connector.  Unfortunately, you cannot always count on fan manufacturers to use a standard color pattern to denote the purpose of each wire.  As you can see in the table below, there’s quite a bit of variance in color coding – even within the same manufacturer.  Improperly wiring your fan may prevent the fan from spinning, or could even cause damage to the fan or motherboard.  Make sure you’re comfortable with a multimeter and test the motherboard pinout for voltage.  Don’t assume!

Fan Color Codes
Fan Wiring Color Codes

Once the proper wiring pattern was established, new fan connector pins were crimped onto the wires and then inserted into a standard 4 or 5-pin fan connector.  The reason a 4 or 5-pin connector will work in this case is that HP uses a 5-position fan header on the motherboard, but one of the pins is unused.  Either a 4 or 5-pin connector will work since both connectors are keyed such that they can only be inserted one way.  Alternatively, you could sacrifice another 4 or 5-pin fan such as the aforementioned AMD CPU fan.  Simply solder the wires with the 4 or 5-pin fan connector in the proper order and simultaneously extend the wiring without having to crimp on new pins.  After the soldering and pinning is complete, be sure to tidy up your wires with some loom or heat shrink to ensure airflow remains optimal in the server chassis.

Ready for action!
Ready for action!

Once all four fans were rewired and inserted into their retention brackets as shown above, the fans were inserted back into their respective slots and plugged into the fan headers.   After the initial POST sequence the fans quieted down to a much more manageable level.  A peek in the BIOS shows that the new fans are idling between 3500 – 4000 RPMs.

Much quieter
Much quieter now

Conclusion

After several days of monitoring, drive and CPU temps appear to be holding steady within a safe range with our new fans.   With room for 12 x 2TB drives, reliable hardware, and a compact 2U form factor the HP DL180 G5 makes a great budget storage platform.  Ours is humming happily along  with 24TB of raw storage and shows that, with a little ingenuity, a server once only suited for a data center can be right at home in a basement or lab environment.