Usable capacity of a mirror or RAIDZ1/2/3 pool, including allocation padding and ZFS reserved space, then the space a Proxmox Backup Server datastore will take for your retention.
Open the calculatorFree tools to size an infrastructure
Ten calculators for the questions you ask before buying disks, signing an SLA or choosing between a server room and a datacenter. Each one shows its method.
Our calculators
Usable capacity, tolerated failures, write penalty, rebuild time and the risk of a read error during the rebuild.
Open the calculatorHow much downtime 99.9% allows per year, month or week, the reverse calculation, and the availability of a chain of components, redundant or not.
Open the calculatorThe data loss and downtime your backups actually allow, step by step: detection, response, transfer back, return to service.
Open the calculatorPower in kW and kVA, yearly electricity cost for a given PUE, heat to remove in BTU/h, and a first estimate of UPS runtime.
Open the calculatorThe throughput a TCP connection really reaches given latency, window and loss, how many streams fill the link, and how long a transfer takes.
Open the calculatorNetwork, broadcast, host range and netmask of an IPv4 prefix; compressed form, /56 or /64 split and ip6.arpa zone of an IPv6 prefix; prefix aggregation and reverse DNS.
Open the calculatorHow long it takes to upload or download a given amount of data at a given speed, in GB or GiB, with network overhead counted, and the bandwidth needed to meet a deadline.
Open the calculatorRuntime from the load, the batteries, their age and the Peukert effect, then when to trigger a graceful server shutdown with NUT or apcupsd.
Open the calculatorTBW ↔ DWPD conversion, lifespan from your writes and the amplification of ZFS, Ceph or a database, and actual wear read from SMART counters.
Open the calculatorTools on our other sites
Six tools live next to the service they relate to:
- Backup window calculator on Nimbus: how long the first upload to a PBS datastore takes, and whether the daily incremental fits in 24 hours.
- Backup retention simulator (GFS) on Nimbus: which backups a keep-daily, keep-weekly, keep-monthly rotation actually keeps, with the PBS prune logic, and the prune job line to copy.
- Downtime cost calculator on our managed services site: what an hour of downtime costs your business, from your own figures.
- Check your machine's time on our NTP site: the offset between your computer's clock and our stratum 1 time servers.
- The exact time on screen on our NTP site: Paris time and UTC synchronised by NTP, and the next daylight saving change.
- Unix timestamp converter on our NTP site: a timestamp in seconds, milliseconds or nanoseconds to an ISO 8601 date and back, NTP timestamps included.
How these tools are built
Every calculator runs in your browser: the values you type are neither sent nor stored. Each page shows its method under the result, with formulas and sources, so you can redo the calculation or challenge it.
Default values are examples, except where the page cites a measurement: those are our own measurements, already published on our sites, with a link to the page that details them. A measurement made on our data is a reference point, not a promise for yours.
Frequently asked questions
Are these tools free?
Yes, with no sign-up and no email address. The calculation runs in your browser and nothing you type is sent to our servers.
Where do the default figures come from?
They are example values, to be replaced with yours. When a page offers a measured reference point, it comes from our own published measurements, with a link to the page that details them. Those measurements hold for our data: they give an order of magnitude, not a guarantee.
Can someone check my calculation?
Yes. Describe your case through the contact form: an engineer reviews your assumptions and gets back to you. It is also the starting point if you want us to run the infrastructure you sized.
Contact
Address
5 B RUE DES NOYERS, 95300 PONTOISE, FRANCE