Shrink guest on hosted platform: Difference between revisions
Shrink guest on hosted platform (view source)
Revision as of 16:42, 15 November 2016
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yum clean | yum clean | ||
Then shut down any services that depend on having enough available disk space to run. | |||
The reason | The reason for this is that we are going to write out zero's to the file system until the file system is full and we do not want any application - for example a database system like mySQL or postgreSQL - to run out of disk space while we are zeroing out the file system. If mySQL would try to write when your disk is full you risk a corrupted database. So this step is important! | ||
Next run: | Next run: | ||
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cat /dev/zero > zero.fill;sync;sleep 1;sync;rm -f zero.fill | cat /dev/zero > zero.fill;sync;sleep 1;sync;rm -f zero.fill | ||
to fill the unused space with zeros. | to fill the unused space with zeros and then remove the "zero.fill" that has all the zero's. | ||
As this command writes | As this command writes to the disk until it runs out of disk space, you will get an error "No space left on the device". This is expected. | ||
==== Zero out unused space on a Windows VM ==== | ==== Zero out unused space on a Windows VM ==== | ||
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Careful! | Careful! | ||
As of sdelete v1.6 -c and -z have changed meanings, many instructions say -c zeros free space, this is no longer the case, it zeros the space then fills with random data in accordance with DOD spec: DOD 5220.22-M, the trigger to zero space with 0x00 has changed to -z! | As of sdelete v1.6 -c and -z have changed meanings, many instructions say -c zeros free space, this is no longer the case, it zeros the space then fills with random data in accordance with DOD spec: DOD 5220.22-M, random data will prevent the reclaim logic from working. | ||
The trigger to zero space with 0x00 has changed to -z! | |||
=== Shrink the disk === | === Shrink the disk === | ||