This update is for HyperCore generations G2, G3, G3+, and HyperEdge G1.  

This update introduces the new secure technology for remote support operations, improved granular file-level recovery,  improved storage performance and storage usage reporting, an updated OS kernel with security and bug fixes, as well as improvements and bugfixes for the replication and retention.

Important Information about updating to this release 

HyperCore appliances with SynetoOS version 4.7.7 and earlier need to be updated in 2 steps: step 1 -  Update to SynetoOS 4.7.9, step 2 - Update to SynetoOS 4.8.5. Since these updates include a major OS kernel update, a reboot will be required. To minimize downtime, the best practice is to combine this update with the ESXi upgrade to version 7.0.3o. The recommended update sequence can be found here.

What’s New

SynetoOS 4.8.5 is not only about security and bug fixes. It significantly improves 3 key features for the HyperCore and HyperEdge G1 users.

Major replication service upgrade

After analyzing customer feedback we made a decision to do a major upgrade of the replication service architecture to better address your use cases. The new replication service architecture was initially introduced in  SynetoOS 4.8.x branch. The replication engine in SynetoOS 4.8.5 brings the 2nd revision with 30 improvements and fixes, but here are 3 main benefits it brings you:

  • Reliable operation, even over unstable networks. Should the connection break, SynetoOS will keep retrying to replicate your VM data. We'll also inform you if the link is down for more than 1 hour.

  • Snapshots are replicated faster on unstable networks. After any connectivity loss the replication resumes where it left by verifying what data is already on the replication target. No time wasted by not sending any data twice.

  • More flexibility. You can now pick the time slots when the replication can operate without affecting your business applications.

Redesigned File level Recovery with enhanced functionality

Since its original release few years ago the File level recovery feature helped hundreds of our customers to recover important data faster and with more granularity than a VM-level restore. With your feedback we are changing the file level recovery to suit your use cases even better. 

Improvements we made in the File Level Recovery service:

  • To make your files available faster and help you meet the 15-minute RTO (Recovery Time Objective) SynetoOS will now intelligently choose the best suitable storage on the host for recovery.

  • To quickly and easily locate the required files in folders with more than 250 files we improved the file browsing to list files about 100x faster. 100K files per folder supported by default, the number can also be increased in settings.

  • To simplify the recovery of large amounts of data in one archive we removed the 10 GB archive size limitation and the 4 GB file size limit for recovery with ISO images.

Secure remote support with Zero Trust, MFA, and full security audit

We are committed to maximize the security and uptime of your infrastructure. To resolve issues quicker and make remote support access 100% secure we have implemented the new remote support engine built around these core abilities:

  • 1-Click authorization for support team access in the SynetoOS web UI

  • Zero trust method of connecting to customer’s machines with multi factor authentication.

  • Added support for connections into restricted environments that do not allow SSH, or ones behind non-transparent HTTPS proxies.

  • Audit for every single connection, with session recordings and playback.

  • Enroll Windows machines in the customer's location, with session screen recording.

  • Optimized reliability for unstable network connections. 

Resolved Issues


Improved system performance by optimizing the system resources we use for SynetoOS routine tasks.

Improved system and storage performance by optimizing replication mechanisms, specifically for environments with high storage loads and 50+ replication schedules.


Together with the replication architecture upgrade we have also addressed multiple issues that rose from

replicating over unstable or slow networks. 

Improved: Added the option to preserve data on the replication target side and improved the communication in a scenario where user tries to synchronize 2 VMs or datastores with no common snapshots found. 

Improved: Made the replication functionality more intelligent and responsive to 3rd party failures.

Improved: Processing of scenarios where a repeated creation and deletion of a replication schedule combined with permanent failover could result in replication freezing. 

Fixed: Replication progress bar only showing a 0% or 100% completion status or reverting to 0% if the replication target became inactive during the replication. 

Fixed: Replication job stays in “In Progress“ state or switches to “Failed“ after it was manually paused. 

Fixed: Replication sends replicas to incorrect targets in scenarios with multiple replication schedules and multiple replication targets.

Fixed: A replication job that is in progress would prevent other replication jobs to start. 

Fixed: Unexpected replication stops in environments with 50+ replication schedules combined with high storage loads.

Fixed: Replication resumes by itself within 3 minutes after it was paused. 

Fixed: Snapshot is deleted in a scenario where replication is started after a snapshot is taken. 

(specific to SynetoOS 4.8.4)

Fixed: UI incorrectly calculated the time for the replication job.

Fixed: Minor UI bugfixes and improvements for replication management and setup.

Failover and Failback

Fixed: In some cases SynetoOS 4.8.4 would not correctly register a VM on the host after failover/feedback.

Fixed: In some cases the UI would keep showing a “Failing Over“ or “Failing Back“ label even after the operation successfully finished. 

Fixed: Failover/Failback button doesn’t work for an unsynchronized datastore. 

Improved: Added a warning message when trying to remove the only snapshot of a datastore. 

File Level Recovery

Fixed: In some environments the mounted virtual disk could not be read.

Syneto Web UI, Monitoring and Alerting 

Improved: Notification email will be sent if scheduled replication was retried for 1 hour and still failed. An email will also be sent if the replication target is offline for more than 1 hour. 

Improved: Added datastore details in the “protection” and “snapshot history” tabs for messages displayed if an app-consistent snapshot failed and a crash-consistent is taken instead.

Improved: Additional email notifications about storage pools running out of space for SerenITy users.

Improved: Credentials and support status processing. 

Improved: SynetoOS replication logging is now more detailed.

Fixed: After failover and failback the UI didn’t display correct information on replication schedules and datastores without a manual page reload.

Fixed: A full data pool is indicated as “Healthy“ and marked green despite the fact there is no space left.

Fixed: The UI shows a false “Failed to take snapshot for VM X. It will be crash consistent.“ error message and email notification in a scenario where the snapshots were setup to be crash consistent. 

Fixed: Snapshot history information not available for a replicated snapshot.  

Known issues 

After the update to SynetoOS 4.8.5 the ESXi ipfilter service may enter maintenance mode. The service will then automatically start without external human intervention. 

After a datastore failover the retention policy on a datastore can change to higher values for both local and remote.

In a situation where an incremental replication is blocked and stops with an error message displayed in the UI and the email notification, the user needs to start a full replication or reach out to support for a workaround.

Due to significant change in the File level Recovery service code, HyperCore systems older than 3 years will not update to the latest version of the service automatically. This will not affect other parts of the system updating to the latest version. For any questions don't hesitate to contact us.

Ongoing Improvements and Future Releases

SynetoOS 4.8.5 continues the series of ongoing updates and new features from Syneto. Your feedback is extremely valuable to help us in our commitment to provide an excellent operating system. Please try out the new release, see what's new, and share your feedback and thoughts to help us shape SynetoOS's future features to bring the maximum value for you.