Compare

What keelOS does, next to the others

One row per feature, including the ones keelOS does not have. Yes means it is in the product today; partial means it works with conditions, by hand, or through third-party pieces. Checked on 2026-10-15 against each product's current documentation; if a cell is wrong, write to [email protected] and we fix it.

	keelOS	Proxmox VE 9	ESXi 8	Hyper-V (Windows Server 2025)	Unraid 7	TrueNAS 25
Host restarts and upgrades
Host system upgraded and restarted while the VMs keep running in memory	Yespause of about 25 s; TCP connections stay up	Noshut down, or suspend to disk by hand	Nosuspend to disk, resume after	Nosaved to disk, restored after	Noshut down, or hibernated by the guest	Noshut down, started again
A VM with a passed-through device kept through a host restart	Yesthe hypervisor runs the IOMMU; the device keeps its DMA mappings	No	Nocannot be suspended	NoSave is not allowed with DDA	No	No
Hypervisor part that must restart with the VMs down	Yesabout 100 KB; rarely changes	Nothe whole system	Nothe whole system	Nothe whole system	Nothe whole system	Nothe whole system
Upgrade with rollback to the previous version	Yestwo boot slots	Partialapt; rollback by hand	Yesprevious bootbank	Partialuninstall the update	Yesprevious version restore	Yesboot environments
Devices
PCIe passthrough of a whole device: disk controller, NVMe drive, network card	Yesdevices listed by serial number, held before the host's drivers	Yes	YesDirectPath	YesDDA, Windows Server only	Yes	Yesexperimental in 25.04
SR-IOV virtual functions of a network card for VMs	YesIntel X710, X550, X540, I350	Yes	Yes	Yes	Partialby hand	Partialby hand
Intel integrated GPU to a VM, with the host's monitor, keyboard and mouse	YesUHD 630 and UHD 770; Windows 10, Linux	Yes	Partialnot supported by VMware; works on some boards	No	Yes	Partialexperimental in 25.04
Intel integrated GPU shared by several VMs (SR-IOV, 12th generation and newer)	YesUHD 770; driver in the product; Windows and Linux VMs	Partialthird-party DKMS module, rebuilt for each kernel	No	PartialGPU-P on client Hyper-V, unsupported on Server	Partialcommunity plugin	No
Discrete graphics card to a VM	Yesone card tested: GeForce GTX 1080 Ti	Yes	Yes	YesDDA, Windows Server only	Yes	Partialexperimental in 25.04
Host CPU and disk temperatures shown inside the guest by standard sensors, no agent	Yes	No	No	No	No	No
Guest desktops on the host's own monitor, switched with Ctrl-Alt-F2…F12, without passing a GPU	Yes	No	No	PartialVMs in windows on the host's desktop	No	No
Guests
Windows 11 with a virtual TPM and Secure Boot, without workarounds	YesBitLocker works; TPM state survives host restarts	Yes	Yes	Yes	PartialTPM yes; Secure Boot reported to need other firmware files	PartialTPM option; state loss reported on 25.10
Windows XP, Server 2003 and Windows 7 with their in-box drivers	YesSeaBIOS; IDE, PCnet, UHCI	Yes	Yes	Yesgeneration 1 VMs	Yes	Partiallegacy boot in Incus by hand
Nested virtualization: Hyper-V and WSL2 inside a Windows guest	Yesfrom the next release	Yes	Yes	Yes	Yes	Partialno documented option
RDP to the VM's console from any RDP client, with sound and clipboard, no guest agent	Yesthe host answers RDP for every VM	NonoVNC, SPICE	Nobrowser console, VMRC	Yesenhanced session, Windows guests	NoVNC	NoVNC, SPICE
Docker and other lightweight containers run directly, next to the VMs	Yeskcells: keel makes a small Docker VM per app from a template or a Compose file; early	PartialLXC; Docker inside a container or VM	No	PartialWindows containers	YesDocker	YesDocker apps
Memory and storage
Unused guest memory given back to the host without overcommit	Yeszero pages reclaimed and lent as disk cache; returned on the first write	Partialballooning, KSM: overcommit	Partialpage sharing, ballooning	Partialdynamic memory	No	No
ZFS under the VMs: snapshots, checksums, send and receive	Yesone dataset per VM	Yes	NoVMFS	NoNTFS, ReFS	YesZFS pools since 7.0	Yes
A VM snapshot covers its disks, settings and firmware variables	Yes	Yes	Yes	Yescheckpoints	Partial	Partial
Management
Web interface, command line and an HTTPS API with scoped tokens	YesEnglish, Chinese, Japanese	Yes	Yes	YesPowerShell, Windows Admin Center	YesGraphQL API since 7.2	Yes
Several hosts managed from one place	Yesa management VM; no cluster, no quorum	Yescluster; Datacenter Manager across clusters	PartialvCenter, paid	YesWindows Admin Center, SCVMM	No	No
Cold migration between hosts from the web interface	Yes2–2.5 s downtime for a small VM; can be taken back for 24 h	Yes	PartialvCenter	Yes	No	No
Live migration between hosts	Being builtrunning VMs already move between pools on one host	Yes	PartialvMotion, paid	Yes	No	No
Shared storage and failover clustering	Nonot planned: each host owns its VMs	Yes	Yespaid	Yes	No	No
Ready-made VM packages from a catalogue: NAS, accounts server	YesMarket: keelNAS, keelAuth, signed packages	Partialcontainer templates	PartialOVA import	No	PartialDocker apps, not VMs	PartialDocker apps, not VMs
BMC (IPMI) settings from the web: network, fan modes, users	Yes	No	No	No	No	PartialIPMI network
Host health page: CPU, memory and disk scores, temperature curves, crash detection	Yes	Partialgraphs, no scores	Partialhardware health	Partialperformance monitor	Partialtemperatures by plugin	PartialSMART, reports
Platform
AMD CPUs	Being builtearly: guests run; no passthrough, no restart with VMs yet	Yes	Yes	Yes	Yes	Yes
Open source	Nothe VMs use only standard formats, see About	YesAGPL	No	No	No	Yes
Licence and price	Yesfree for personal use; commercial use with our permission	Yesfree; paid enterprise repository and support	Partialfree 8.0 U3e edition; vSphere paid	Partialwith a Windows Server or Windows Pro licence	Nopaid licence	Yesfree Community Edition

Product names belong to their owners. The keelOS column says what the current release does; the feature pages and the release notes have the details and the measurements.

Sources

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