Glossary Storage Systems, Protocols, and ScalePetabyte

Petabyte

A petabyte is one thousand terabytes. The useful way to think about it is file count rather than capacity: a petabyte of video might hold a few hundred thousand files, while a petabyte of simulation or sequencing output can hold hundreds of millions. The second one is much harder to manage, at the same capacity.

Key takeaways

A petabyte of video and a petabyte of sequencing data can differ a thousand times in file count.
File count matters more than capacity when managing a petabyte.
An exabyte is one thousand petabytes, and a zettabyte is one thousand exabytes.

How many terabytes are in a petabyte?

1,000 terabytes, in the decimal units that storage vendors use. Operating systems sometimes count in binary units instead, where 1,024 tebibytes make one pebibyte, which is why a drive or a system can look slightly smaller once it is in use. For planning, 1 petabyte equals 1,000 terabytes, or 1 million gigabytes.

How many files are in a petabyte?

It depends on file size. A petabyte of files that average 1 MB is about a billion files. The same petabyte of 1 GB video files is about a million files. File count often matters more than capacity for storage work, because scans, backups, and migrations slow down with the number of files, not only their size.

How long does it take to index a petabyte?

It depends on how many files the petabyte holds, not on its size. Indexing reads one metadata record per file, so a petabyte of large video files, about a million of them, can be indexed in minutes, while a petabyte of small files, about a billion of them, takes hours. For scale, Diskover has indexed 1.4 billion files in 2 hours on three nodes, about 200,000 files per second. After the first scan, rescans that skip unchanged folders run much faster.

What is an exabyte?

An exabyte is one thousand petabytes, or one million terabytes. At that scale, file count matters even more than capacity, because every management job, from indexing to tiering, works one file at a time. An exabyte of small files can hold hundreds of billions of them, which is why scale is planned in files as well as in bytes.

What is a zettabyte?

A zettabyte is one thousand exabytes, or one billion terabytes. It is used to describe the amount of data created or stored worldwide rather than the size of one organization’s estate.