The volume of disks for the portal for industrialists

Started by Cody Babcock, Nov 07, 2022, 06:57 AM

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Cody BabcockTopic starter

Hi all. I have an order from a client to create a portal, or rather a social network, for an industrial company. It has 96,000 employees (working in several countries). The essence of the social network is sharing photos and short videos on the company's tools (how to use, how to launch, etc.). The problem is the following - how to calculate how much you need to allocate HDD for these needs to employees? I will say right away the video will be limited to 1 minute. Initially, I thought to offer the customer a server with 30 TB (6 disks of 5 TB each), but after counting all the pros and cons, I'm not sure that this will be enough. Of course, you don't need so much right away, but I also don't want the customer to come back with claims after 6 months that the disks are full.


A hard drive is the most valuable component in any computer. After all, it stores the information that the computer and the user work with, if we are talking about a personal computer. Every time a person sits down at a computer, he expects that the operating system loading screen will now run through, and he will start working with his data, which will be issued "on the mountain" from his depths of the hard drive.

If we are talking about a hard disk, or even an array of them as part of the server, then there are dozens, hundreds and thousands of such users who expect to get access to personal or work data. And all their quiet work or rest and entertainment depends on these devices, which constantly store data in themselves. Already from this comparison it can be seen that requests to hard drives of the home and industrial class are presented unequally – in the first case, one user works with it, in the second – thousands.
It turns out that the second hard drive should be more reliable, faster, more stable than the first one many times, because many users work with it and hope for it. This article will discuss the types of hard drives used in the corporate sector and the features of their design, allowing to achieve the highest reliability and performance.

SAS and SATA drives are so similar and so different

Until recently, the standards of industrial and household hard drives differed significantly, and were incompatible – SCSI and IDE, now the situation has changed – SATA and SAS (Serial Attached SCSI) hard drives are overwhelmingly on the market. The SAS connector is universal in form factor and compatible with SATA. This allows you to directly connect to the SAS system both high–speed, but at the same time small capacity (at the time of writing - up to 300 GB) SAS drives, and less high-speed, but at times more capacious, SATA drives (at the time of writing up to 2 TB). Thus, in one disk subsystem, it is possible to combine vital applications that require high performance and prompt access to data, and more cost-effective applications with a lower cost per gigabyte.

Such constructive compatibility is beneficial to both manufacturers of rear panels and end users, because at the same time equipment and design costs are reduced.

That is, both SAS devices and SATA can be connected to SAS connectors, and only SATA devices are connected to SATA connectors.

SAS and SATA – high speed and large capacity. What to choose?

  The SAS disks that replaced the SCSI disks completely inherited their main characteristics of the hard drive: spindle speed (15,000 rpm) and volume standards (36,74,147 and 300 GB). However, the SAS technology itself is significantly different from SCSI. Briefly consider the main differences and features:
The SAS interface uses a point-to—point connection - each device is connected to the controller by a dedicated channel, unlike it, SCSI operates over a common bus.

SAS supports a large number of devices (> 16384), while the SCSI interface supports 8, 16, or 32 devices on the bus.

The SAS interface supports data transfer rates between devices at speeds of 1.5; 3; 6 GB/s, while the SCSI interface does not have a bus speed allocated to each device, but is divided between them.

SAS supports connecting slower devices with a SATA interface.

SAS configurations are much easier to install, install. Such a system is easier to scale. In addition, SAS hard drives have inherited the reliability of SCSI hard drives.

When choosing a disk subsystem - SAS or SATA, you need to be guided by what functions will be performed by the server or workstation. To do this, you need to decide on the following questions:

1. How many simultaneous diverse requests will the disk handle? If it is large, your unambiguous choice is SAS disks. Also, if your system will serve a large number of users, choose SAS.

2. How much information will be stored on the disk subsystem of your server or workstation? If more than 1-1.5 TB – it is worth paying attention to a system based on SATA hard drives.

3. What is the budget allocated for the purchase of a server or workstation? It should be remembered that in addition to SAS disks, you will need a SAS controller, which also needs to be taken into account.

4. Do you plan, in the future, an increase in the volume of data, an increase in productivity or an increase in the fault tolerance of the system? If so, you will need a disk subsystem based on SAS, it is easier to scale and more reliable.

5. Your server will work with critical data and applications – Your choice is SAS disks designed for severe operating conditions.

A reliable disk subsystem, it is not only high-quality hard drives of an eminent manufacturer, but also an external disk controller. They will be discussed in one of the following articles. Let's look at SATA disks, what types of these disks there are and which should be used when building server systems.