Developers Club geek daily blog

Stories from practice of optimization of a network

1 year, 9 months ago
Hi! I with colleagues optimize the available channels. We are constantly confused to optical sealants, to engineers-cablemen, in general, to loaders.



And our work is an analysis of a stack of protocols and its complete rearrangement under features of the channel, setup of the optimum sizes of a frame, collecting of several packets for the channel with big latency in one, a deduplication, normal compression, analysis of SSL and reassembly with the same certificate. It is solved in the simplest case installation of special iron on the accepting and transmitting end. As it is necessary to reach each point, we also work as exit engineers. And, as at any exit engineers, stories at us the sea. Below I will tell a little, I will only change a number of minor circumstances that it was impossible to recognize the customer.

For example, there are night works in very large shop. The administrator of the customer and our engineer came per hour nights into server, work. The engineer left in a toilet, returned. In a couple of minutes – knock at a door. Open — and at once GBR with automatic machines, at once legs for the body, a muzzle in a floor and in handcuffs flies.

Then approach police and main on shop. Main assesses a situation and with authority declares:
— I know this, this is our administrator. And I do not know this. Take away.

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Work as "IT astronaut": as we, engineers, visit bears and seals

1 year, 9 months ago


"Devil. Start the astronaut" — the phrase with which our most difficult departures begin. I remember, for last Christmas approximately so we also went to repair ABHM of one public institution. The machine froze, and the data-center from it was heated. From that, we will repair or not, depended as elderly people over all country will spend New Year (with pension or without). Rescued, but work was still that. Then it was calculated and added. Pension.

Since then we are also called astronauts because we work in the block heater. At least a half of departures is at most an hour on picking and week somewhere where instead of Habr only bears. And even money costs nothing.

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3D - laboratory for people from MIEMA, putting the head in prototypes of trace of printed circuit boards

1 year, 10 months ago


At the end of 2014 the MIEM new educational and administrative complex of Higher School of Economics National Research University in Strogin where many different abrupt things for training of students are implemented was put in operation. One of such projects — laboratory for prototyping of electronic and computing means. Under this business the small budget was selected, we are selected as the contractor. Further we solved not absolutely typical problem of creation of the room where around you fly different virtual 3D - objects. For example, that it was convenient to understand electronic chips.

It was necessary to apply creative imagination and just that mathematics which is vigorously mastered by students to achievement of effect of the return projection (when you pass it by the screen, but the shadow at the same time on it is not cast).

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Network monitoring: as we monitor that all nodes worked for the large companies

1 year, 11 months ago

By the form this optics going on the wood to a collector it is possible to conclude that the assembler did not observe technology a little. Fastening on a photo also prompts that it is, probably, the seaman – a node sea.

I from command of ensuring physical operability of a network, in other words – the technical support which is responsible for that bulbs on routers blinked as it is necessary. We have "under a wing" different large companies with infrastructure over all country. In their business we do not climb, our task – that worked a network at the physical control layer and the traffic passed as it is necessary.

The general sense of work – permanent poll of nodes, removal of telemetry, runs of tests (for example, check of settings for search of vulnerabilities), ensuring working capacity, application monitoring, a traffic. Sometimes inventories and other perversions.

I will tell how it is organized also to steam of stories from departures.

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Different counters for automation of office: repatters, curtains, lighting and so on

1 year, 11 months ago


Hi! Now I will show a heap of toys which help to make life at office better. For example, not to fight because of repatters and at first sight to understand its loading. I will tell what rake happens how to do correctly in advance and what to do if in advance did not leave, and it is necessary to improve very cheap office space already tomorrow.

Let's begin with booking systems a repatter and informing on what there now occurs. Traditionally it is here such screens plates as it is given above on a photo. Ours at office with a touchscreen, a calendar and still a heap of features, normal — just the monitor and web service to it looking in the intranet of the company.

There are 3–5 normal industrial solutions of the series "put and do not touch for years" are vendors of AMX, Crestron, Extron and others. Actually, it is top brands, and they have all solution stack: video routing (it is necessary for those situations when on a panel the video call to the manager is clicked), switching, display.

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As we did HD Wi-Fi at stadium on 33 thousand people in the Krasnodar region in what features of a dense covering, and why Wi-Fi to the fan specifically consist

1 year, 12 months ago
Can seem that Wi-Fi at stadium is not necessary in general. Came to be ill – so look behind game, but do not post a selfie and read mail. But is not present, Wi-Fi is necessary for two important reasons. First, at such accumulation of people channels of a cellular network will be extremely quickly disassembled, and the most part of fans will remain for a while without phone. Secondly, actually, owners of stadium very much wanted to give special mobile application for all fans.

Inside – schemes of arrangement of players in the field, statistics on a match and players, plus strimingovy video from cameras that it was possible to see close up in persons on the tablet or phone what occurs. Well and at once repetitions of important points from different foreshortenings.


On radio inspection


Result of inspection of a membrane

For all this fast Wi-Fi of high density and with the minimum interferentsionalny phenomena is necessary. Here not to stick normal hotspot – good examination of radio inspection, plus the special equipment is necessary. Result – 150 cunning access points with beamforming after enough nontrivial works.

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As it is possible to make fault-tolerant data storage system of domestic servers

2 years ago

Cluster note: server of domestic production of Etegro (2 AMD Opteron 6320, 16 GB RAM, 4 HDD)

The data storage systems used now in practice in Russia conditionally share on three categories:
  • Very expensive high-end SHD;
  • Midreynzhevy arrays (tiring, HDD, hybrid solutions);
  • And the economic clusters on the basis of SSD arrays and HDD arrays from "household" disks which are often collected by the hands.

And not the fact that last solutions more slowly or less reliable, than hayend. Other approach which is not always suitable for the same bank, for example is simply used absolutely. But perfectly is suitable for almost all medium business or cloud solutions. — we take the general sense a lot of cheap nearly "household" iron and we connect in fault-tolerant configuration, compensating problems the correct software of virtualization. Example — domestic RAIDIX, creation of the St. Petersburg colleagues.

And here EMC known for the devilishly expensive and reliable pieces of iron with software which allows to lift without problems both VMware-farm, and virtual SHD, and any butt on same h86 servers has come to this market. Also the history has still begun with servers of the Russian production.

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We have received GOLD on operation of TsOD TIER III — final achivka after T-III on the project and T-III on ready object

2 years ago


Data-centers are evaluated on fault tolerance levels from I to IV. These levels happen TIA (which are not demanding check, it is simple according to the statement) and Uptime Institute (with rigid certification). TIER III assumes possibility of work at failure of any of nodes in any place of infrastructure. If it is pipe with coolant — there has to be the second same. If it is fuel tank, there has to be the second spare. If this cooling — there have to be reserves on chiller of N+1, etc.

At first this compliance to the TIER III level was established on the project. We protected documentation: roughly speaking, Aptaym's engineers "crossed out" any node and looked, whether the rest will be able to work. Many pass this quest.

The following step — to pass certification on ready object, that is to confirm compliance of documentation and to the principles of fault tolerance already on the implemented object. This the most difficult in Russia because to declare in the plan and to construct — two big differences. The special charm to process was added by customers who have already brought on site the produktiv. Therefore the passable check — very abruptly.

The third step — we have received certification on operation. That is have confirmed that the team and all processes correspond to the principles of Uptime. Such TSODOV in Russia only 2 pieces.

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Romanticism of distant engineering departures (and our rat has survived)

2 years ago

"— Come on, chyo, the truth is impossible so? Conveniently, cable multicore, soft. In single-core so you will not turn..."

The customer — the big company — announces the tender for the UPS and conditioning for infrastructure of the data-centers over all country. It is slightly less than 30 pieces of objects, and including the cities where there is no railroad. Generally. In August starts competition, in November the design of all documentation only just comes to an end. Respectively, our engineers come already while "outside" from-30 to-40 fresh airs. And under the terms of the contract it is necessary to wash the outside block of the conditioner.

Who does not know, I report — it becomes vodka. It is desirable — fake, it is frosted over worse. Procedure such: the box or two in the nearest shop, galvanized bucket is bought. At this moment passersby already start reacting extremely painfully, watching draining of vodka in bucket. Vodka, by the way, in many remote cities — still alternative currency is stronger than ruble. Then on faces of people around the genuine grief and all world pain when the block of the conditioner starts being washed out appears.

We always send to such departures at least one engineer with experience of similar works because there is a lot of reefs. Beginning from that for sacrilege can is banal to beat, and finishing with that the vodka box should be carried out then somehow on accounts department "houses". And questions will be. One more danger — at raspryskivaniye on the external block of the conditioner it is possible to inhale extremely quickly alcohol vapors. As the skilled joke — in tool palette it is necessary to have compartment for cucumbers to remove effects of inhalations of this kind. The following problem — everything should be done quickly because at-35 and below taking into account condenser temperature about 60 degrees in plus — the vodka smell promptly extends on the area in the direction of wind. Or vsenapravlenno, if the wind is not present. Locals really start behaving and looking for concern source very strange.

Come, I will share other stories.

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Optimization of communication links for mining in the north of Russia

2 years ago

When we went to mounting, nearby got tractor from ravine

There are such severe Russian men who extract different minerals which were meanly grouped in hard-to-reach spots. It is often simple to reach and pull out them from under the earth happens very much and very expensively. Therefore the developed infrastructure on site production — unusual occurrence. And so, in the Far East in many places optical fiber — the section still of science fiction, and the wire meets in the wild nature only if to bring it with itself in hands.

Communication is made via the satellite there. Respectively, requirements for the channel grow, but to extend very painfully and expensively — satellite resource not the scalablest, and through it to drive gigabytes it will not turn out.

We solved problem of optimization of the channel due to compression of traffic and prioritizing of applications in channels that the most important always went the first. The whole network detective story has turned out.

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