Linux Storage
LVM
- LVM cannot contain a bootable partition, which means that you’ll need to create a separate /boot partition.
- Physical volumes The physical disks or partitions that LVM splits into physical extents.
- Volume groups The collections of physical volumes; the giant pools of storage made up of all the physical extents.
- Logical volumes LVM has created a virtual hard drive, the volume groups, so it also needs to create virtual partitions –or logical volumes. They can be formatted with a filesystem,used to store data and mounted into the main directory tree, just like normal partitions
- /etc/fstab: /dev/VolumeGroupName/LogicalVolumeName /home ext4 defaults 0 1
vgextend VolumeGroupName /dev/sda2 # add new physical volume to a volume group lvextend -L8G /dev/VolumeGroupName/LogicalVolumeName # extend logical volumes within the volume group use the extra available storage just added resize2fs /dev/VolumeGroupName/LogicalVolumeName # cause an ext4 filesystem to expand to the same size as the newly modified logical volume
pvmove / vgreduce
File System
Btrfs
Btrfs is a new filesystem for Linux, designed to help deal with the large storage systems that are common in data centres and other industrial settings. It provides a strong set of management tools and other advanced features.
Btrfs removes much of the need for LVM and, since all of this is rolled into a single filesystem, with no more partitions or logical volumes to deal with, admin is massively simplified. What’s more, the system is safer – thanks to features such as online filesystem check, checksums, and filesystem mirroring, that other filesystems you would have
used with LVM are lacking.
Rescue
testdisk / photorec
Tools
GParted (partitioning), g4u (disk clone), Partimage, Testdisk (Recover lost partitions and repair boot sectors), Foremost (Recovers files based on their headers and other internal structures)
MySQL Error
phpMyAdmin Import Error:
SELECT `comment` FROM `phpmyadmin`.`pma_column_info` WHERE db_name = 'xxx' AND table_name = '' AND column_name = '(db_comment)' #2006 - MySQL server has gone away
» my.ini | max_allowed_packet = 100M
Access Denied for user ‘root@…’:
/usr/libexec/mysqld -u root –skip-grant-tables
WordPress Security
Default “wp_” as a db prefix, this is a known vulnerability, malicious users can exploit your data easily.
Symfony Xampp Command Line
Control Panel -> System -> Advanced System Settings -> Environment Variables… -> Path -> add “;C:\xampp\php\” -> Create a cmd shortcut:
jQuery DOM
$(‘body :hidden’).show()
$(‘#back-to-top’).parents(‘#footer’).children(‘ul’).find(‘a’)
$(‘.comment ‘).closest(‘.block’).andSelf().filter(‘[class*=level2-], [class^=level3-]‘)
.siblings()
.next()
$(‘img’).wrap(‘<p></p>’)
$(‘img’).unwrap()
.remove()
.empty()
.detach()
.attr()
.removeAttr()
.text()
.val()
jQuery Events
jQuery Events
.click(fn)
$(‘h3.cat-title’).bind(‘click’, catClick) // easier to unbind later
function catClick(evt) {
$(this).parent().childrent(‘div.cat-desc’).slideToggle();
}
$(‘a’).click(function(){
return false; // prevent redirect
}); Read more
jQuery Effects
jQuery Effects
.show()
.hide(500)
.toggle()
.fadeOut(500)
.fadeIn(500)
.fadeTo(500, .5)
.slideUp(500)
.slideDown(500)
.slideToggle(500)
.animate({
opacity: 0.4,
left: “+=50px”
}, 1000 );
jQuery Selector
jQuery Selectors
contain: *=
endwith: $=
$(‘:not(li)’)
$(‘.category li:not(:first)’)
$(“p[class]“).css(“border”, “none”);
$(‘tr[class="1"]:first
tr[class="2"]:visible’).size();
$(“ul:has(li[class=a])”)
$(“ul li:nth-child(3)”)
$(‘.left-nav li:even’)
$(“img”, this);
$(this).find(‘img’); Read more
