Developers Club geek daily blog

Productivity of disk systems of the HP ProLiant DL360 servers from Gen5 to Gen8. Everything that you did not know and were afraid to ask

3 years ago
We constantly face standard task about expansion of office server for the different companies. Most often the client wants to buy the server on which postfix + as *SQL, ejabberd will work with the same * SQL, samba, and also * SQL under 1C office mail, for example. In this case there is need of studying of productivity of disk arrays in relation to servers of "working group" of the same model, but different generations. As our company more specializes on products of Hewlett-Packard, the HP ProLiant 360 servers of the 5th, 6th, 7th and 8th generations have undergone the analysis 1U:

In all configurations of the controler we use cache the size 256Mb. It should be noted difference in the flow capacity of PCI Express of the bus by means of which controlers are connected: P400i and P410i — 2GBps (gigabyte per second), P420 — 8 GBps (gigabyte per second).

The first question which logically arises in this case: in what parrots to measure productivity? Having studied article of dear amarao, we have established that similar measurements should be taken at least in two parameters: IOPS — quantity of disk Input/Output of operations per second: the their is more, the better and Latency — operation processing time: the it is less, the better.

It has been decided to make performance comparison of different configurations in relation to different standard tasks as these tasks mean different options of load of disk subsystem. Character of loading is defined by the following parameters: block size, ratio of operations reading record, accidental/serial access.

Serial access to data is characteristic for record of various logs, during the broadcasting and record to audio/video and volume of the similar. Essence that access is characterized by the localized disk area, without need to jump on all surface.

Accidental access is most characteristic for databases, web and file servers: large number of requests to the sectors scattered on disk.

The combined combines both is higher described the scenario, for example functioning of DB with record of logs on the same array.

We test directly raw-device (direct access, without thinking about file system) to avoid influence of features of implementation of file systems and everything that with it it is connected on different platforms.
Under this task rules for fio and IOMetter have been written.

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Side-by-side execution of dependent tasks and synchronization with condition variables in shell

3 years ago
How to synchronize parallel shell processes, using named pipes (FIFO files) as condition variables. How to execute in parallel dependent tasks in topological order with minimum of means: POSIX shell, mkfifo, POSIX kernel. As parallel start accelerates loading of the built-in systems and * BSD (rc-stage FreeBSD from 27 to 7 seconds) or start of applications in the user containers Docker, LXC and jail. As it raises aptaym in failover clusters of Jet9.

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LinuxCon 2015 and everything, everything, all: impressions

3 years ago
I will not compete in skill of writing of reportings with dzeban together with which I was lucky to visit conference LinuxCon Europe Linux developers. Therefore I will try to light simply that to me was most of all remembered, and thus to add picture.

My impressions are not attached to chronology of conference. I in general will tell about conference and the most interesting reports with links to presentations and the corresponding sites. I ask under kat.

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The maker-up's life in Linux

3 years ago
Most of fronted-developers, use Windows or OS X OS due to the lack of full-fledged Photoshop. But how to be that who is not indifferent to Nix to systems? Now also we will try to find out, I ask the interested under kat.

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Menu of choice of Thinstation session

3 years ago
At the second Thinstation version there was menu of choice of session when loading — Replimenu. Though it was awful and sometimes drove in stupor of the unprepared user who has got used to full-fledged graphics mode, but worked. In the fifth version it "has broken", and developers have not fastened any replacement, the question "Where the Menu Has Got to" have answered:
If you said that replimenu was a menu system to act as a low resource substitute for a window manager, then no, machines that low in resources, that they cannot have both a window manager and an application in memory have not been manufactured for over 10 years and are no longer on the support radar.
that in loose translation means — such computers that there is not enough memory, years 10 as do not make, yuzayta the window manager with icons on desktop.
Such approach to solution did not suit me and therefore I have decided to make the menu for session choice, the benefit functionality of Thinstation it allows.

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Thinstation, we are connected to the server of Linux terminals on XDMCP

3 years ago
After reading of posts and manuals about Thinstation there can be impression that it is intended only for connection to the Windows servers on RDP in the various ways, but I here even more often use it for the organization of terminals of connection to Linux-servers for XDMCP.
Upon transition to the version 5 developers have decided to get rid of direct connection to the H-server which was set by the option "SESSION_#_TYPE=x", now they advise to use Xnest, and it is necessary only for start of the H-server in window. Why it is made I has not understood, has only noticed minus that connection systematically falls and assembly swells on excess 1,4 Mb. In the latests version and so more and more modules of kernel integrate it is direct in it, the image of system is loaded in consequence of that all more long and more long so excess megabytes are unnecessary us.

What not to understand causes and effects of such solution of developers it was necessary to write unpretentious "bag" of initialization of connection via the standard X-server without laying. I share …

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Use of hardlinok (hardlink) for incremental backup of Synology DSM

3 years ago

The DSM system is rather convenient and by default in system modules which close 95% of needs of the private (and not really) the user that is called "from box" are installed.

There is also embedded system of backup: Backup &Replication. Simple, clear and reliable. As the network destination in the server can use either similar Synology, or rsync.

Unfortunately this system is not able to do incremental backup. The most primitive way to bypass it — to configure separate backup on each day of the week. Thus we will have 7 folders with backup copies, but obvious minus — storage of the full copy in each folder — volume can turn out such that not everyone will afford such storage.

So — we will configure full-fledged incremental backup.

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Start of the DOS application in Linux

3 years ago
Need of start of DOS applications under Linux arises infrequently, but happens. Here somehow and to me it happened, has decided to share experience, maybe, to whom it is useful.

And it was necessary to start someone, once written application for policlinic working at Foxpro under DOSOM in Linux since money for purchase of Windows of licenses was not.

Basic data:
Suse Linux Enterprise Desktop 10.3 — workstations.
Suse Linux Enterprise Server 10.3, on it sphere on Samba (I also shared before for work with Windows of workstations since on the license for the Win-server too money was not), name spheres, strangely enough — SHARE.
There was all 2-3 years ago therefore SLED and SLES versions at the time of installation were not such and ancient.

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Solution of the problem of installation of display resolution in Thinstation

3 years ago
Throughout the previous articles (We save electricity on thin clients, Connection of two printers to Thinstation and their binding to ports, Monitoring and management of Thinstation 5.x) I will continue to impart Thinstation setup experience.

With transition to Thinstation-5 often there is problem of the "wrong" display resolution though the option SCREEN_RESOLUTION = *** x *** and is defined.

Developers for some reason drag this glitch from the version in the version, despite my messages in the bug tracker. It is necessary to correct every time manually.

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We save electricity on thin clients

3 years ago
For the purpose of power saving at work there was directive: for the weekend and holidays, and also for the night, all computers, except critical, have to be switched off. But as usual — someone yes will hammer will forget. For thin clients there are two solutions — to lift TSmon and from it to drive or will be connected to the client on ssh and to give command on switching off.

By and large process simple — we add sshd packet to assembly, we set the password for root in the build.conf file the param rootpasswd parameter, we collect image, we load when it is necessary we log in on ssh on the client and we switch off, but it is more interesting to send to all necessary clients signal on switching off by one team, without excess gestures.

Why not telnet — because on ssh is simpler to make autologin, without crutches like perl and expect. Further the way of implementation is described.

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