***On Feb 7, 2013, at 3:03 PM, Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > > TRIM probably does reduce the need for the firmware to do its own static wear leveling, but I don't know if it's that significant except for large deletions. In this case it helps via dynamic over provisioning. Less over provisioning is needed if unused pages/blocks can be made available (erased). ***On Feb 7, 2013, at 6:08 AM, Adam Goryachev <mailinglists@xxxxxxxxxxxxxxxxxxxxxx> wrote: > > Though, like I said, would adding an extra SSD to the RAID5, and > reducing the size of all partitions by 20%, and then doing TRIM on that > newly freed space, would that improve performance because of the extra > free space the SSD can "work with" ? It might help eventually, but I don't think this is the magic bullet you're looking for. Have you looked at network congestion when this problem is happening? > Basically, on occasion, when a user copies a > large file from disk to disk, or when a user is using Outlook > (frequently data files are over 2G), or just general workload, the > system will "stall", sometimes causing user level errors, which mostly > affects Outlook. Does this concern anyone else? In particular the user doing "disk to disk" large file copies. What is this exactly? LV to LV with iSCSI over 1gigE? Why did you reject NFS for these physical Windows boxes and their VMs to access this storage, rather than what I assume is NTFS over iSCSI, because of this statement? > Each LV is then exported via iSCSI That block device needs a file system for Windows to use it. It also seems to me one or more of these physical servers running VMs, with only 1gigE to the storage server, need either additional pipes LACP or bonded ethernet, or 10gigE. I can just imagine one person doing a large file copy disk to disk, which is a single pipe doing a pull push, double NTFS packet overhead, while all other activities get immensely hit with network latency as a result. ###On Feb 7, 2013, at 4:07 AM, Dave Cundiff <syshackmin@xxxxxxxxx> wrote: > See page 17 for a block diagram of your motherboard… > Your SSDs > alone could saturate that if you performed a local operation. Get your > NIC's going at 4Gig and all of it a sudden you'll really want that > SATA card in slot 4 or 5. Yeah I think it needs all the network performance and reduced latency as he can get. I'll be surprised if the SSD tuning alone makes much of a dent with this. Chris Murphy-- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
