macOS 27 does not support CoreStorage volumes

Original Article ↗ Hacker News Discussion ↗

Apple’s macOS 27 removes support for CoreStorage volumes and effectively strands encrypted HFS+ setups, breaking some backup workflows and legacy Fusion Drive-style configurations. Commenters also report regressions such as worse performance, battery life issues, and the loss of FireWire drive support, criticizing Apple’s willingness to drop older technologies with little warning. Many are rethinking their backup and storage strategies—experimenting with APFS on HDDs, NAS-based Time Machine, or ZFS—while contrasting Apple’s aggressive deprecation with Microsoft’s stronger focus on backward compatibility.

CoreStorage removal and relation to LVM

  • Some describe CoreStorage as “macOS’s LVM,” but others argue it’s only loosely similar and missing many LVM features.
  • Its primary visible use case was Fusion Drives and encrypted HFS+ volumes; several commenters consider it effectively dead tech.
  • There’s confusion about what “expensive storage hardware” is actually rendered useless; most think almost everything can be migrated or reformatted.

Fusion Drives and tiered storage successors

  • Users miss the transparent SSD+HDD tiering of Fusion Drives; many current NAS setups (e.g., cache + HDD array) require manual data movement.
  • Alternatives mentioned include bcachefs tiering, Windows Storage Spaces, and simply moving to full-SSD setups, though some still prefer large HDD arrays for cost.
  • Consensus: SSDs are the practical “successor,” but automatic hybrid solutions are still appealing and under-served.

HFS+, APFS, and encrypted backups

  • Loss of CoreStorage breaks encrypted HFS+ workflows, especially for Time Machine and long-term archives.
  • APFS is said to “work” on HDDs but is widely reported as painfully slow for Time Machine compared to HFS+.
  • Users discuss switching to APFS despite performance, or moving to third‑party tools (SuperDuper, Carbon Copy, Borg, ZFS).
  • Some highlight HFS+ data-rot issues as a reason to move away anyway; others emphasize Apple’s history of dropping technologies once they stop using them.

FireWire and legacy device support

  • macOS 27 (or earlier 26) drops FireWire support, surprising users who still rely on FW drives and specialized devices (audio, video, imaging, film scanning).
  • Lack of clear warning is criticized; people note daisy-chained adapters and older OSes/VMs as possible workarounds, but these are fragile.

macOS 27 quality and platform direction

  • Multiple reports of 27 being a “disaster”: lag, crashes, CPU spikes, DNS glitches, and reduced battery life versus earlier releases.
  • Some see it as further “iOS-ification” and fear eventual tighter lockdown (App Store-only installs, locked bootloaders), though others note such predictions have not materialized yet.
  • Apple is portrayed as prioritizing pruning and new features over long-term backward compatibility, in contrast to Microsoft.