[Solved] Have we gotten to the point that SSDs are worth it yet? - Page 2

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any thoughts on using ssd's w/ an ssd raid controller vs using software raid? My main interest is in running raid0...

what about a system with ssd's & an ssd raid controller (at raid0) and 1 backup hdd... i.e. one logical ssd drive running everything --OS, apps, games, file storage, etc.?

comments appreciated!

thanks!

Modern SSDs use "raid0" or interleaving already internally - the Intel controller has 8 channels, which can be compared with 8 disks in RAID0.

Some 'bad' SSDs like OCZ Apex try to enhance performance by putting low-level RAID0 with two SSD controllers; but this won't make it a good SSD as it suffers from extremely high write latencies causing 'stuttering' or periodic freezes for small writes which happen on any system disk.

But if you want to put several Intel SSDs in RAID0 using onboard RAID or software RAID, there should be no obvious disadvantage. Just make sure to partition correctly; Windows Vista and Windows 7 creater proper partitions at 1024KiB offset, while XP creates them at 31.5KiB offset which would degrade performance and cause more wear on the SSD due to a misalignment issue.

So as long as you use Vista and higher, you should be fine. Intel onboard RAID or software RAID is recommended. Avoid any JMicron/Silicon Image/Promise FastTrak RAID drivers or PCI-based RAID cards, as these may degrade performance and generally offer weak RAID implementations with little benefit to the user.

Onboard RAID would be faster in some cases, as Hardware RAID cannot keep up with the IOps processing rate. This goes even for high-end Hardware RAID controllers such as Areca (which i own) with true Intel IOP RAID chips and dedicated DDR2 memory. These are very fast for HDDs and processing RAID5 I/O, but they are not fast enough to process the thousands of IOps a setup you described could process.

One Intel X25-M 80GB G2 (not even the SLC version but MLC) would have a maximum IOps rate of 40.000 random read IOps, while the Areca controllers with Intel IOP seems limited to 70.000 IOps. With onboard RAID you can get to 100.000 IOps which is a milestone as this performance level used to be exclusive to supercomputers. Now it's achievable with just 4 Intel X25-M 80GB G2 disks and Intel onboard RAID.

Onboard RAID is actually driver RAID and allows the usage of the extremely fast hardware you have in your machine. Hardware RAID would add to processing latency, thereby reducing the IOps rate. It is its own bottleneck so to speak. The Intel drivers also allow usage of write-back mode via the 'write caching' option, which can be very useful to enhance performance though at increased risk of corruption in case something goes wrong (so be sure to have backups). But if we are talking performance, the best setup would be:

• Windows 7
• 4 x Intel X25-M 80GB G2 (MLC is fine; you dont really need the SLC version)
• Intel ICH10R onboard RAID0
• Write caching option enabled
• Reasonably fast multi-core CPU

Some would argue onboard RAID reduces performance due to it slowing down your CPU. This is untrue in reality, due to a number of reasons:

• If there is disk access, the CPU is most likely doing nothing and waiting for disk input anyway
• CPUs are extremely fast and the amount of work needed to process I/O is no match for modern CPUs
• Modern CPUs have multiple cores, which especially on windows get under-utilized; even with CPU-heavy work at the background there will be likely zero performance hit due to other cores being able to handle the work
• Even if there is any performance hit due to lower CPU performance, it would be offset by higher I/O performance, so overall performance should always be higher

In case of Hardware RAID there is a penalty for each I/O request due to added latency of processing time by the RAID controller itself; which uses a much slower CPU than the one in your main system. This latency is not important when writing, but it is when reading, because in case of blocking I/O the application is frozen/unresponsive until the I/O request data has been returned to the application; and it resumes operation. With HDDs this can be regularly 'felt' as applications do not respond anymore and do not draw any graphics. Moving the windows would show 'garbage' and clicking the menu's or buttons would not respond until the I/O has been completed.

The behavior of such applications is due to an obsolete single-threaded design still many applications use. Many programmers do not realise each GUI application should be multi-threaded and the I/O should be done "asynchronously" to cope with such problems and provide the user with a resposive experience without any visible or noticeable slowdowns. Even with slow disk I/O these multi-threaded applications would instantly respond to user input, at the cost of increased programmer complexity.

So to conclude: onboard-RAID or software RAID would be fastest, using the chipset-provided SATA ports. Next come PCI-express softRAID controllers, then come Hardware RAID controllers due to their increased latency which are kind of useless to SSDs due to them slowing them down instead of speeding them up. Hardware controllers have optimizations that work on HDDs only; hurting performance on SSDs instead.

Well, now I've used 785GB on the WD. I've dug up some money to get a Caviar Black 2TB at best, but more likely a Hitachi Deskstar 2TB. Anyway, like suggested I've moved the 6GB swap file from my SSD to the WD Caviar. The Caviar lost performance, no difference on the SSD, so I'll be moving it back, plus HDD Tune still reports that it has 89% life left after ~5 months of use, equals total life of around 4 years, and that's with the page file on it. Plus, I noticed that bootup was slightly slower.

Screens:

Oh, and keep in mind that my PC is still faster with an SSD even though 99% of my apps are installed on my WD HDD. But it'll still be faster because that 110 MB/s drive is dedicated solely to that single program, not having to worry about the OS, page file, etc.

Although, due to my TV recording, home videos, FSX recordings, etc., I've now used nearly 800GB out of 900 on my WD 1TB. So soon, I'll have my WD Caviar Black 2TB for storage, the 1TB for apps and overflow storage, and the SSD for the OS, swap file, and select apps. (Like ones that don't let you select where to install them)

And my bottleneck for Video recording is not my CPU, but merely the app I use to do it. Prism video converter until like a week ago, it would only use 1 CPU. Now it can use 2 CPUs, along with the ability to convert multiple files at a time, so it usually does itilize at least most of my '8' core i7. However, it won't convert more than 1 FRAPS video at a time, and will crash if you try to do that, and that's what I convert most of time. (Fraps AVI vids are like 4GB for 2.5 minutes, converted to MPG with minimal quality loss is 500MB for around 11 minutes.)

The three storage drives I'm considering:

Hitachi Deskstar 2TB
WD Caviar Green 2TB
WD Caviar Black 2TB

The black is only if I can scrape up some extra cash. This drive will fill up my last HDD slot and SATA slot. (My other 3 HDD slots are stuffed with extra wires and my 8 SATA slots are being occupied by my 2 HDDs, 3 ODDs, and 2 eSATA Converters)

And by the way, with the swap on my HDD, every once in a while it'll randomly lock up for a second or two.