Limiting your options doesn't improve your chance of success The unpacked files take up the same space on the server. If you have to add another hard drive, no big deal, it just adds backup for the files. Continually accessing the files in the archive uses cpu too, about the same time as unpacking the archive. php has a sleep function, you could let it sleep(10); between unpackings to allow the server to do other jobs.
You have to choose between something that 'sorta' works and something that works.
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