Hello, I'm using 3TB Hitachi Deskstar 5K3000 drives in a custom 45 drive high density enclosure (http://blog.backblaze.com/2011/07/20/petabytes-on-a-budget-v2-0revealing-more-secrets) and need to limit the inrush current at startup by stagger the drive spin-up. Since I can't control drive power through by backplanes, the best way to do this appears to be by enabling the Power-Up In Standby feature on the drives via 'hdparm -s1'. Unfortunately this is not working for me.... I believe the problem I'm having is that the Hitachi Deskstar 5K3000 drives require a SET FEATURES subcommand to spin-up to active state when the device has powered-up into Standby. I'm getting this from section 9.1 in the following spec: http://www.hitachigst.com/tech/techlib.nsf/techdocs/FFDF1FA949853DBD8825785A005CBC55/$file/DS5K3000_US5K3000_OEMSpecRev1.1.pdf Section 4.17 in the ATA spec that I found at http://t13.org/Documents/UploadedDocuments/docs2006/D1699r3f-ATA8-ACS.pdf says the following: A device may implement a SET FEATURES subcommand that notifies the device to spin-up to the Active state when the device has powered-up into Standby. If the device implements this SET FEATURES subcommand and power-up into Standby is enabled, the device shall remain in Standby until the SET FEATURES subcommand is received. If the device implements this SET FEATURES subcommand, the fact that the feature is implemented is reported in the IDENTIFY DEVICE or IDENTIFY PACKET DEVICE data. . . . If the device does not implement the SET FEATURES subcommand to spin-up the device after power-up and power-up into Standby is enabled, the device shall spin-up upon receipt of the first command that requires the device to access the media. Section 7.47.8 then says: Subcommand code 07h shall cause a device that has powered-up into Standby to go to the Active state (see 4.17 and figure 7). >From this I'm concluding the following: 1) Not all drives require the spin up subcommand which explains why this works for some drives 2) Our Hitachi drives require this command and the libATA drivers don't appear to support it Is this right? If so, is there a reason why the libATA does not support this feature? I'm running Debian 5 with a 2.6.32 kernel... Has this been implemented upstream? Would this be a feature hard to add/backport? Thanks, Tim-- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
