Selecting hybrid RAID mode?

Question

Iron

Initial data: a terminal server based on core i7 (I know that it's rogue, but there is no money for anything else) for 15 users. Five work in 1C, five in a specialized CAD, the rest in ms office. Now it costs 32 GB X25-E INTEL SSD as a system disk and two sata III terabytes for data.
Required: to create a "relatively" trouble-free file system (we are not talking about other components yet).
After reading a review of RAID controllers on one of the sites (I will not indicate the source - it is easily googled). I settled on the Adaptec 6405E - I'm satisfied with the price and the ability to create hybrid systems. I also plan to order two INTEL SSD S3500 series (by the way, where can I get it in Ukraine? On ebay 160 gb costs $214 + $60 shipping, which is not very encouraging). Right hereuse cases are described.
Now the question is: - How best to organize the array? Or do the classics: two RAID 1 arrays: one on SSD for the system, the second on SATA for data; or as described in the Adaptec manual in example 4, but to be honest, I did not understand the advantages over the classics. Maybe someone has come across this controller and can shed some light on my questions?

Answer 1

Making an array for the system on an SSD definitely does not make sense on the server, access to the system disk on the server is minimal. On the SSD on the server, you need to store data that is often read / written, and with random access to the disk, not sequentially. Most often, these are databases. HybridRAID technology makes sense when data is often read but rarely written, for example, in the same databases for a web service, this is also not your case.
In your case, I would not bother at all and made RAID 1-0 on SATA.

Answer 2

hybrid raid (Raid 10 2SSD 480 + 2 HDD WD RE 500)) works fine on ESXi. Compared to raid 10 on conventional HDDs (WD RE 500) and Raid6 on 8 2TB WD RE is much faster. Just mega faster. Tasks Zabbix, EAMil, System disks of virtual machines. The load is small - 10-15 users. But I think this technology is simply excellent. Judge for yourself reading like on an SSD. And writing to an array is usually cached - on a controller with 2 GB - this is quite enough for caching the record. In general, for recording, you just need a larger cache if a lot of information is written. You can cache the RAM well, or by means of a controller that allows you to create a cache from an SSD. In general, for my hybrid raid tasks, that's it. I think it's great for databases. Moreover, in this version, unlike any "hot" caches

Answer 3

I suggest considering this configuration:
use 4 disks for data in raid 10.
+ High reliability, building a read speed compared to 5/6
- "Relatively" more expensive to
use SSD disks for preparative data (temporary files, temp database for sql and applications)
4 disks with an R / W ratio of 70/30 and 30% cache hit, you will get about 215 iops, which is quite enough for 10-15 users, and data processing on SSD disks can significantly level potential queues when working with large amounts of data (reports 1c , cad processing, loading-unloading )

Answer 4

Who used hybrid raid as a volume under VMware ESXi share your experience. How it works? Does it work? what speeds? What tricks? Are there any restrictions on choosing an SSD? For example, the size of the logical sector they emulate? This may be the experience of using the volume on which the VMs were spinning, while the ESXi hypervisor itself was on a different volume, or maybe both were present on the same hybrid raid volume. Now I mean exactly hybrid raid technology, not SSD caching, which only individual controllers can do there, in my opinion, Adaptec's Q series and not LSI CashCade technology, but a simple Russian hybrid raid, which is built just like a regular raid from HDD, but due to the simple asymmetry of the reading algorithms, it gives a serious increase in speed. Let's say the one that Adaptec has a 6th series - without support for 4KN drives. I'm primarily interested in the speed of random read or database. I have an idea to install raid 1 ESXi and a few Wirths on such a volume. lift cars on it, incl. database server. The bases are small, the servers are all loaded unevenly and will be idle 95% of the time. What do you think?