Wake on LAN with linux

My always on Linux machine is a dell FX 160, very low power consumption, should work as my VPN, asterisk server, and wake up other computers when i need them, the device itself is multi homed, So i basically need it to wake up other devices on one of the networks

The commands you need for this to work are as follows

etherwake -i eth1 xx:xx:D2:B2:30:C9 (My laptop)

eth1 is the network connected to my mini linux server that is connected to the target network.

Thats all there is to it, in addition to enabeling wake on lan in your BIOS

Windows 10 slow shutdown on SSD (Solved)

SSDs are the best thing that happened to computer boot time (and many other things) since the invention of the abacus

But for some reason, booting up is faster than shutting down, much faster, Shut downs are taking a long time (Or reboots)

So let me see what i can do about this

1- Windows ClearPageFileAtShutdown is something that happens before shut down, and is my first guess to why this is happening
So let us set the following key to zero (0) and see if this speeds up shutdown time.

HKEY_LOCAL_MACHINE\CurrentControlSet\Control\SessionManager\Memory Management then ClearPageFileAtShutdown set to (0)

This session should shut down slowly, the next time you boot, shutdown will be much faster.

The other thing that i am thinking is relevant is changing the location of the indexing service index files to my spinning disk, this is because the spinning disk has thousands of files, and i would like to keep my SSD fast for certain other applications.

CP overwrite files in destination

Although the copy program cp in Linux overwrites without prompting, in practice, it does not, the reason behind that is that the command is aliased with the (cp -i), you can check that by using the alias command

So there are 2 solutions to this to make cp overwrite

The first would be to unalias, while the second would be to execute the command directly with

\cp

Or you can use the full path to the alias command like

/usr/bin/cp

I personally use

\cp this that

Aligning your Samsung 840 EVO – Slow disk problem

This probably applies to both 840 evo and 850 evo, but not the EVO 840 PRO and the 850 evo pro because the pro are not TLC

All over the internet, people are saying that solid state drives don’t need to be aligned because they will scramble the used flash cells anyway for wear leveling.

This is absolutely NOT TRUE, although wear leveling does work that way (in a simplified way), the mapping algorithm that levels the writes maps blocks to other blocks.

So here is how it works, let us assume there was no wear leveling, when the partition is not properly aligned to a starting offset which is a multiple of the eras block size, writes and erase operations that should require the erasing of one block could end up erasing and writing to two blocks, now the block is a hardware restriction, so when the wear leveling algorithm selects a new location, the problem of sing two cells instead of one is still valid.

Don’t take my word for it, mess up the alignment of one of your partitions, then examine reads and writes of 512 or 4K, both will be much slower.

Now, what you need to do is to align the file system to block size

Because this disk has a 1.5M erase block 1536 KiB and to be sure we want it to also align with 2048 KiB (Just in case the erase block is not the whole story), you can set the sector alignment value to 12288 (6144 KiB), which is a multiple of 1536 KiB and 2048 KiB.

So, in LINUX, even though it is usually correctly aligned by the partitioning software (And in windows it is already done for you and if not it can be done by samsung’s magician software), you can check the current alignment with.

fdisk -l /dev/sdb

For your own math, the EBS (Erase block size) on those drives is 1.5MBs

So basically, 12288 is 3*4k, the three comes from the fact that it is a three level cell (TLC)