SAS vs Enterprise SATA?

Question

SAS

I would like to dispel the myths about SAS.
Tasks - medium and large enterprises, data centers. (storage on 24+ hdd)
Is it worth using SAS to get it without compromising finances:
1. Performance (sequential read speed, random IOPS).
2. Ease of administration.
3. Reliability.
4. All previous points together.
The question arose due to the fact that SATA ssds easily outperform SAS hdds.

Answer 1

Previously, in the pursuit of iops, there was no choice but to tell, and then sas, now the prices for ssd have fallen and you can safely play with them without forgetting to reserve them, these ssds are falling, unfortunately.
If a gigantic volume is boring, then there is definitely sat. If ipos is needed, then I would take an ssd. In my opinion, the further development of ssd and the fall in prices for them will kill the market for sas and fc screws.
The points.
1) Sequential reading is not much more than that of a sata, and for the most part in a raid it rests on the pci-e bus with 24 screws, you can read at a speed of 2.1 gigabytes per second. At random, yes sas is better because of the high turnover, filling and protocol.
2) I don’t understand at all what could be the convenience of administration here? If you take a hotswap, then it depends on the case. In the raid controller, everything is also the same for sas and for sata for the most part.
3) I didn’t notice more reliability in the sas, they also fall approximately, they also change under warranty for two years for new ones. With the presence of the sixth, first and 10 raids, the reliability of the screws becomes a secondary factor. Well, it broke, well, I replaced it in the server with a new one, well, I changed the broken one to a new one under warranty. That for sas, that for sata operations are exactly the same. Ssd by the way is much more paduchi compared to conventional screws.

Answer 2

The question arose due to the fact that SATA ssds easily outperform SAS hdds.

Um, well, at least decide what you are comparing: either hdd with different interfaces, or ssd and hdd. And then I can name PCI-E SSD - they are even faster.

Answer 3

As for reliability, it depends on what to compare with, if with mass desktop screws, on which the MTBF is not standardized at all, then it’s not a myth, if with a similar SATA class, some kind of constellation, for example, then everything is already much closer. The point is not in SAS as such, but in the fact that SAS is not made for home use.
The second point is speed, and it can be critical, especially in a random game, and replacing with solid-state drives is often still not very realistic.
If we talk about the differences in the interfaces, then this is a greater noise immunity, better error correction, etc. Which ultimately reduces the chance of a problem on this side, and they happen, although not often.
As to whether it is worth the money, a question that can only be answered in a particular case, knowing all the nuances. In most cases, no. But they are just not made for most cases. =)

Answer 4

1) At random, yes sas is better because of the high turnover, filling and protocol.

No one doubts that there is some kind of performance increase, is it worth the money?

2) I don’t understand at all what could be the convenience of administration here?

For example, advanced monitoring systems, etc.

I didn’t notice more reliability in sas, they also fall about

This is one of the myths about SAS - reliability.

Answer 5

IMHO, here again it is necessary to dance from tasks. From my own experience I will say that I have not worked with CACs for a long time, there is no need. Large volumes - SATA hard drives in raids, and on decent controllers the linear speed pleases. The random access speed on 7200 hard drives is clearly not a fountain, but I would not say that CACs with 10k rpm offer something much better, and the cost is much higher.
Yes, and on SATA hard drives 7200 you can have random speeds approximately like on CACs from 10k rpm or even higher, google for a combination of short working stroke.
Need high IOPS? Take an SSD, the same Crusial M4 with firmware 009 is quite reliable, but there are a lot of reviews in terms of speed, I won’t repeat it.
Well, if you want both large volumes and high speeds of random access, sorry, but you have to pay well. Instead, think about how you can optimize data storage so that caches and frequently used data can be moved to SSD, and the rest to arrays from hard drives. Or different servers.
And the last thing - for SATA2 hard drives, it’s still behind the eyes and ears (we don’t take into account the use of expanders), but for SSD I highly recommend using SATA3, naturally for those who hold it.

Answer 6

Now you can write a post with a clear conscience - “Exposing the conspiracy of hard drive manufacturers !!! "SAS is not needed."? :)

Answer 7

in large storages, it is better to increase the iops by the number of disks and by increasing the cache. Although, of course, each task has its own infrastructural approach. For example, a high-density storage bitblaze.ru But SAS is still not very relevant now, although it is alive and a little in demand