^1 Windows/Linux/Mac/iOS/Android/BlackBerry - Supported operating systems for thick client (native binary application), which provide background data transmission and setting services.^2 Zero knowledge - The user needs to manage their own encryption key or password. If they lose it, there is no way to access the data. The service provider cannot access the user's data even if required by the government. Backup service providers often claim that no one can access the users data even though they themselves could if forced to do so, so entries claiming support of this feature should always have a supporting reference. If the backup service has a password recovery or reset mechanism that allows a user to access their data when they lose their password or key, that proves they do not have zero knowledge.^3 Secure Key Management - If yes, the user holds and controls of the encryption key. If no, the service provider holds and controls the encryption key.^4 Payment options/plans:Limited MB plan - Pay per computer. Additional fee for storage over a threshold.Unlimited MB plan - Pay per computer. Storage per computer is unlimited.$/MB plan - Pay per unit of storage, but unlimited computers may share that storage.^5 Cloud hosted Net Drive - Cloud can serve storage over WebDAV, SMB/CIFS, NFS, AFP or other NAS protocol, allowing files to be streamed from the cloud. A change made to the cloud is immediately accessible to applications on all clients without needing to pre-download (sync) the file in full.^6 P2P storage - data spread over many computers based on peer-to-peer net advantages.^7 Sync - Synchronization between computers, and/or mobile devices (PDA, MDA,...)^8 Public Internet file hosting -^9 Restore via physical media -^10 Server location - countries where physical servers are located. Where the data will be located.^11 Still in Beta version^12 Whether the desktop client (if available) can detect and upload changes without scanning all files.^13 Many backup services offer a limited free plan, often for personal use. Often it is possible to increase the free backup limit through coupons, referrals, or other means that are not included in this column. This column also does not include free trials that are only available for a limited period of time.^14 External hard drive support - Can refer to an alternate backup destination or whether the service can back up external drives.^15 Hybrid Online Backup works by storing data to local disk so that the backup can be captured at high speed, and then either the backup software or a D2D2C (Disk to Disk to Cloud) appliance encrypts and transmits data to a service provider. Recent backups are retained locally, to speed data recovery operations.^16 Unlimited BW - If bandwidth capping or limits are used on accounts.AcronisUp to five PCs, always incremental backups, remote access from the web
AltDriveData de-duplication; block-level incremental; unlimited offering. Home (1–3 computers) or biz service (1–1000 computers). Client-side encryption, external USB drives, NAS support for Biz customers.
BackblazeData de-duplication; block-level incremental.
Barracuda Backup ServiceData de-duplication; real-time hybrid on-site/off-site data back-up.
blaucloud No User Limit each User get his ownCloud Instance in an encrypted Storage.
BullGuard Backup5 PC/license, fast upload speeds, mobile access, encrypted transfer and storage, password-protected settings, free 24/7 support.
CarboniteBlock-level incremental, Home or Pro editions. iPhone/ Blackberry/
Android App available to remotely access data from the online backup (For Pro: Users of the computer which are backed up, not available for the Administrator of the Pro). Can manually select files to upload that are larger than 4 GB.
CrashplanUnlimited destinations. Data de-duplication; block-level incremental. Can run server-free, exchanging backup space with friends and family.
Datashield High-level encryption, personalized encryption key, shared cloud drive, sync folder functionality .
DattoFocused on business continuity and total data protection for small and medium businesses. Offers instant virtualization of backed up instances locally or securely in the cloud. Datto maintains its own private cloud with 250+PB of protected data in 9 data-centers.
Dolly DriveCloud storage that is specifically designed for the Mac. Also allows users to store files exclusively in the cloud for seamless access on any computer or mobile device.
DiinoiPhone/Android app available.
DropboxData de-duplication, delta sync, iPhone/Android/Blackberry app available.
Dropmysitewebsite backup, database backup, SFTP support, free up to 2 GB.
EgnyteDelta sync, Google Docs sync, user and group management
ElephantDriveAuto-transfer from defunct Xdrive.
FilesAnywhereMark Cuban acquired minority interest in 2006. Android,
iOS,
BlackBerry apps available. Dedicated server options available. CoolBackup software used for backup and sync.
F-Secure[Steek acquired by F-Secure July 2009]
HumyoHumyo was acquired by Trend Micro and will become part of Trend Micro SafeSync. Humyo no longer accepts new clients.
IASO BackupAdvanced data reduction technology. Data de-duplication mechanism. High level of scalability and cost effectiveness.
ICFilesSecure File Share Storage. Proprietary license download client. High level security, SOC 2 TYPE II, ISO 27001,27017, 27018, CSA, PCI, HIPAA, CJIS, EU Model Clauses, on request private servers for FISMA and FedRAMP.
IDriveProprietary license download client. Automatic Selection. Continuous Data Protection. "Virtual drive" explorer.
Jungle DiskProprietary license download client sample code.
KeepVaultReal-time hybrid on-site and offsite data backup.
MemopalCross-user de-duplication, delta sync.
MiMediaInitial seed via a
MiMedia-owned external hard drive available (no extra cost, shipping included).
MozyData de-duplication; block-level incremental. "Mozy Data Shuttle" physical seeding service available for extra fee.
ReplicaliaProfessional Backup for Professional Data.
pCloudData de-duplication. Zero Knowledge Privacy with client-side encryption.
SpiderOakData de-duplication."Zero Knowledge" encryption.
StoreGrid Cloud Byte-level incremental backup, local backup, Disk Image backup - BMR and physical seeding.
SyncplicityGoogle Docs sync, Central Management with Business Console.
TaniBackup (Cheap Backup) Up to 10 TB per standard package. Extensible to over 300 TB per single account. Access via SMB/CIFS or SSH (including sftp, scp, rsync and so on). 100 GB for $2 per month.
TarsnapClient source available; data de-duplication; block-level incremental.
TeamDrive Store encrypted data on any WebDAV server; supports working offline; files can be commented; built-in support for conflict resolution.
Tencent CloudTencent is offering users 10GB of free cloud storage
Unitrends Vault2CloudData de-duplication; hybrid on- and off-premises data backup; physical seeding.
UpdateStar Online BackupData de-duplication; block-level incremental.
Usenet backupIs the method of storing backup data on the usenet.
Windows Live MeshReplaces windows live sync and windows live folder.
Zetta Enterprise-grade Online BackupSupports
Linux, Mac OS, and Windows, high speed WAN optimization, SAS 70 certified data centers.
Zmanda Cloud BackupAvailable in German and Japanese languages, supports MS SQL Server, MS Exchange, SharePoint, MySQL Database, System State, Oracle.
Any changes can be undone, and files can be undeleted.
AcronisSupports detailed history of changes to files with browsing by date or version number.
AltDriveOld versions of files are kept for 60 days. Biz customers choose their retention policy of 30 days to 7 years to forever.
BackblazeOld versions of files are kept for 30 days.
blaucloud Keeps old version if versioning app is activated (included in all plans even FREE) until users runs out of storage.
Box Versioning is included in paid subscription
CarboniteKeeps old versions for up to three months. It keeps one version for each day of the past week, one version for each of the previous three weeks, and one version for each of the previous two months that the file has been backed up. Versioning available for PC computers only; not available for Mac.
CrashplanOptions: All, or staged (daily, then weekly, etc.).
Cubby All previous versions and deleted files are kept until explicitly removed by the user or the user runs out of space. All deleted files and previous versions count towards the storage limit.
Dolly DriveYes. Keeps unlimited versions of files.
DropboxBy default, Dropbox saves a history of all deleted and earlier versions of files for 30 days for all Dropbox accounts.
DropmysiteProvides incremental backups with the ability to download every snapshot.
ElephantDrive Any number of versions can be kept for any amount of time.
Google DriveOld versions of files are kept for 30 days or 100 revisions. Revisions can be set not to be automatically deleted.
IASO Backup All versions of files can be kept for different periods of time, starting from 1 month to 1 year or more.
ICFiles No files are kept after delete, auto delete clears at every 24 hours.
iDrive Up to 10 old versions of files are kept forever (until explicitly removed).
Mozy Old version of files are kept for 30 days. Pro 60 days, Enterprise 90 days.
pCloudVersioning is included for free (30 days) and paid plans (180 days). Deleted files can be restored within the same timeframes.
PowerFolder Five versions are kept online. In the client it is configurable how many versions to store locally.
SOS Online Backup (Infrascale)All versions are kept. Only the largest counts towards the storage limit.
SpiderOakAll versions are kept. All files can be undeleted.
SugarSyncFive versions are kept. Only the most recent version of each of existing files as well as deleted files count towards the storage limit.
SyncplicityOld versions of files, as well as deleted files, are kept for 30 days. Configurable for business or enterprise-class services.
TeamDrive All previous versions are kept and can be restored.
Tresorit Versioning is included in paid subscription
Zetta Enterprise-grade Online BackupAll versions are kept. All files can be undeleted.
Other features and limitations
Other notable limitations or features.
Baidu CloudMust be registered by verified phone first.
BoxPerformance degrades after 10,000 files in sync folder. Technical limit of 40,000 files in sync folder. Does not sync .tmp files, Outlook PST files, hidden files (hidden folders are synced), or any file or folder with /*?":<>| in the name.
DropboxPerformance degrades with more than 300,000 files in sync folder. This is a soft limit.
pCloudCan exclude certain file types (e.g., .tmp files) with a file type exclusion filter.
SugarsyncLimited to 80,000 files per top level sync folder. To workaround, you can create multiple syncing folders, but each top level folder is limited to 80k files. Also, Microsoft outlook and Apple iTunes databases are unsupported.
Bitcasa closed its services in February 2017.Copy was discontinued on May 1, 2016 Dell DataSafe was discontinued on June 11, 2015.drop.ioNorton Zone was discontinued on July 7, 2014.Trend Safesync (not included in the table above) is no longer available and existing accounts will be purged on January 31st 2017.Ubuntu One was discontinued on June 1, 2014.Windows Live MeshWuala was discontinued on November 15, 2015.XdriveZumoDrivePogoPlug, discontinued online backup services September 28, 2016