The OCZ Vector 180 (240GB, 480GB & 960GB) SSD Review
by Kristian Vättö on March 24, 2015 2:00 PM EST- Posted in
- Storage
- SSDs
- OCZ
- Barefoot 3
- Vector 180
Mixed Random Read/Write Performance
Mixed read/write tests are also a new addition to our test suite. In real world applications a significant portion of workloads are mixed, meaning that there are both read and write IOs. Our Storage Bench benchmarks already illustrate mixed workloads by being based on actual real world IO traces, but until now we haven't had a proper synthetic way to measure mixed performance.
The benchmark is divided into two tests. The first one tests mixed performance with 4KB random IOs at six different read/write distributions starting at 100% reads and adding 20% of writes in each phase. Because we are dealing with a mixed workload that contains reads, the drive is first filled with 128KB sequential data to ensure valid results. Similarly, because the IO pattern is random, I've limited the LBA span to 16GB to ensure that the results aren't affected by IO consistency. The queue depth of the 4KB random test is three.
Again, for the sake of readability, I provide both an average based bar graph as well as a line graph with the full data on it. The bar graph represents an average of all six read/write distribution data rates for quick comparison, whereas the line graph includes a separate data point for each tested distribution.
The Vector 180 does better in mixed 4KB random IO than the 850 Pro, but it's a bit slower than the rest of the drives.
Fortunately the power consumption is still excellent.
 |
|||||||||
Vector 180's problem is its low random read performance because the performance gets better as more writes are thrown into the mix.
Mixed Sequential Read/Write Performance
The sequential mixed workload tests are also tested with a full drive, but I've not limited the LBA range as that's not needed with sequential data patterns. The queue depth for the tests is one.
In mixed sequential tests the Vector 180 does slightly better in the sense that the difference between drives in the order of 10% when excluding the 850 Pro.
Similar to what we saw in the sequential tests, the write power consumption is fairly high, which also increases the average power consumption and the Vector 180 no longer enjoys an advantage over the other drives.
 |
|||||||||
Vector 180's "bathtub" curve is pretty average, but as we can see here the power scales as soon as the portion of writes is increased, which isn't unique but for instance the 850 Pro and Extreme Pro don't exhibit such behavior.
Facebook
Twitter
RSS
89 Comments
View All Comments
nils_ - Wednesday, March 25, 2015 - link
It's an interesting concept (especially when the Datacenter uses a DC Distribution instead of AC), but I don't know if I would be comfortable with batteries in everything. A capacitor holds less of a charge but doesn't deteriorate over time and the only component that really needs to stay on is the drive (or RAID controller if you're into that).nils_ - Wednesday, March 25, 2015 - link
"I don't think it has been significant enough to warrant physical power loss protection for all client SSDs."If a drive reports a flush as complete, the operating system must be confident that the data is already written to the underlying device. Any drive that doesn't deliver this is quite simply defective by design. Back in the day this was already a problem with some IDE and SATA drives, they reported a write operation as complete once the data hit the drive cache. Just because something is rated as consumer grade does not mean that they should ship defective devices.
Even worse is that instead of losing the last few writes you'll potentially lose all the data stored on the drive.
If I don't care whether the data makes it to the drive I can solve that in software.
shodanshok - Wednesday, March 25, 2015 - link
If a drive receive an ATA FLUSH command, it _will_ write to stable storage (HDD platters or NAND chips) before returning. For unimportant writes (the ones not marked with FUA or encapsulated into an ATA FLUSH) the drive is allowed to store data into cache and return _before_ the data hit the actual permanent storage.SSDs adds another problem: by the very nature of MCL and TLC cells, data at rest (already comitted to stable storage) are at danger by the partial page write effect. So, PMF+ and Crucial's consumer drive Power Loss Protection are _required_ for reliable use of the drive. Drives that don't use at least partial power loss protection should use a write-through (read-only cache) approach at least for the NAND mapping table or very frequent flushes of the mapping table (eg: Sandisk)
mapesdhs - Wednesday, March 25, 2015 - link
How do the 850 EVO & Pro deal with this scenario atm?
Ian.
Oxford Guy - Wednesday, March 25, 2015 - link
"That said, while drive bricking due to mapping table corruption has always been a concern, I don't think it has been significant enough to warrant physical power loss protection for all client SSDs."I see you never owned 240 GB Vertex 2 drives with 25nm NAND.
prasun - Wednesday, March 25, 2015 - link
"PFM+ will protect data that has already been written to the NAND"They should be able to do this by scanning NAND. The capacitor probably makes life easier, but with better firmware design this should not be necessary.
With the capacitor, the steady state performance should be consistent, as they won't need to flush mapping table to NAND regularly.
Since this is also not the case, this points to bad firmware design
marraco - Wednesday, March 25, 2015 - link
I have a bricked Vertex 2 resting a meter away. It was so expensive that I cannot resign to trow it at the waste.I will never buy another OCZ product, ever.
OCZ refused to release the software needed to unbrick it. Is just a software problem. OCZ got my money, but refuses to make it work.
Do NOT EVER buy anything from OCZ.
ocztosh - Wednesday, March 25, 2015 - link
Hello Marraco, thank you for your feedback and sorry to hear that you had an issue with the Vertex 2. That particular drive was Sandforce based and there was no software to unbrick it unfortunately, nor did the previous organization have the source code for firmware. This was actually one of the reasons that drove the company to push to develop in-house controllers and firmware, so we could control these elements which ultimately impacts product design and support.Please do contact our support team and reference this thread. Even though this is a legacy product we would be more than happy to help and provide support. Thank you again for your comments and we look forward to supporting you.
mapesdhs - Wednesday, March 25, 2015 - link
Indeed, the Vertex4 and Vector series are massively more reliable, but the OCZ hatersignore them entirely, focusing on the old Vertex2 series, etc. OCZ could have handled
some of the support issues back then better, but the later products were more reliable
anyway so it was much less of an issue. With the newer warranty structure, Toshiba
ownership & NAND, etc., it's a very different company.
Irony is, I have over two dozen Vertex2E units and they're all working fine (most are
120s, with a sprinkling of 60s and 240s). One of them is an early 3.5" V2E 120GB,
used in an SGI Fuel for several years, never a problem (recently replaced with a
2.5" V2E 240GB).
Btw ocztosh, I've been talking to some OCZ people recently about why certain models
force a 3gbit SAS controller to negotiate only a 1.5gbit link when connected to a SATA3
SSD. This occurs with the Vertex3/4, Vector, etc., whereas connecting the SATA2 V2E
correctly results in a 3Gbit link. Note I've observed similar behaviour with other brands,
ditto other SATA2 SSDs (eg. SF-based Corsair F60, 3Gbit link selected ok). The OCZ
people I talked to said there's nothing they can do to fix whatever the issue might be,
but what I'm interested in is why it happens; if I can find that out then maybe I can
figure a workaround. I'm using LSI 1030-based PCIe cards, eg. SAS3442, SAS3800,
SAS3041, etc. I'd welcome your thoughts on the issue. Would be nice to get a Vertex4
running with a 3Gbit link in a Fuel, Tezro or Origin/Onyx.
Note I've been using the Vertex4 as a replacement for ancient 1GB SCSI disks in
Stoll/SIRIX systems used by textile manufacturers, works rather well. Despite the
low bandwidth limit of FastSCSI2 (10MB/sec), it still cut the time for a full backup
from 30 mins to just 6 mins (tens of thousands of small pattern files). Alas, with
the Vertex4 no longer available, I switched to the Crucial M550 (since it does have
proper PLP). I'd been hoping to use the V180 instead, but its lack of full PLP is an issue.
Ian.
alacard - Wednesday, March 25, 2015 - link
In my view the performance consistency basically blows the lid off of OCZ and the reliability of their Barefoot controller. Despite reporting from most outlets, for years now drives based off of this technology have suffered massive failure rates due to sudden power loss. Here we have definitive evidence of those flaws and the lengths OCZ is going to in order to work around them (note, i didn't say 'fix' them).The fact that they were willing to go to the extra cost of adding the power loss module in addition to crippling the sustained performance of their flagship drive in order to flush the cache out of DRAM speaks VOLUMES about how bad their reliability was before. You don't go to such extreme - potentially kiss of death measures - without a good boot up your ass pushing you headlong toward them. In this case said boot was constructed purely out of OCZ's fear that releasing yet ANOTHER poorly constructed drive would finally put their reputation out of it's misery for good and kill any chance a future sales.
OCZ has cornered themselves in a no win scenario:
1) They don't bother making the drive reliable and in doing so save the cost of the power loss module and keep the sustained speed of the Vector 180 high. The drive reviews well with no craters in performance and the few customers OCZ has left buy another doomed Barefoot SSD that's practically guaranteed to brick on them within a few months. As a result they loose those customers for good along with their company.
or
2) The go to the cost of adding the power loss module and cripple the drives performance to ensure that the drive is reliable. The drive reviews horribly and no one buys it.
This is their position. Kiss of death indeed.
Ultimately, i think it speaks to how complicated controller development is and that if you don't have a huge company with millions of R&D funds at your disposal it's probably best if you don't throw your hat into that ring. It's a shame but it seems to be the way high tech works. (Global oligopoly, here we come.)
All things considered, it's nice that this is finally all out in the open.