Posts by ServerOk

Connecting to VNC Server from a Mac computer

On Windows and Linux there are many free open source VNC clients available. For Mac, if you google, most VNC clients are paid. But you don’t need a VNC client on Mac. To connect to VNC server from Mac Computer, go to terminal, run following command

See Mac, VNC […]

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proxychains allow you to route traffic using proxy servers. This is useful for routing traffic throihg applications that do not support proxy by default. For example, i use ssh through proxy chains. To install proxychains on Ubuntu, run

Now you need to edit /etc/proxychains.conf and add your proxy servers.

On my computer, i […]

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Nginx upstream sent too big header

Plesk Nginx

When i login to a PrestaShop web site, i get error on a Plesk server.

On checking error login for the site in folder /var/www/vhosts/, i found following error message proxy_error_log:2020/11/25 19:41:41 [error] 1809#0: *39664 upstream sent too big header while reading response header from upstream, client:, server:, request: “POST /en/login?back=my-account HTTP/2.0”, […]

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Server Load

Here are some useful commands to check server load. iostat shows disk IO usage. %iowait shows how much time process wait for disk operation. This should be 0. If you are on VPS, check for %steal to see if host server is overloaded.

Checks for processes in ā€˜Dā€™ state

Top processes using CPU […]

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Find MySQL Database and Table Size

To find size of database using SQL command, run following SQL in MySQL promt.

Example FInd disk usage by tables To find disk usage by tables in database, run

In above SQL, replace DB_NAME_HERE with actual name of the database. Example

See MySQL […]

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Requesting a zone trasnfer with dig

To request a zone transfer using dig, use


See dig […]

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