Open-E JovianDSS ver.1.0 up01 Release Notes

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Revision as of 12:30, 31 July 2014 by migrate>Da-B
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Known issues

Using Sync always, Sync standard and Sync disabled

    Sync always for Zvol is the safest option and is set by default. However, it can cause write performance decreases since all operations are written and flushed directly to the storage. In case of using sync always, it is recommended using mirrored write log.
    Sync standard option improves the write performance, but some (cached) data can be lost in case of a sudden power failure. Use this option only in environments equipped with UPS.
    Sync disabled gives the highest performance, but can be a dangerous option. Use it only when necessary and on UPS protected environment.

Browser recommendations

    It is strongly recommended to use Mozilla Firefox browser to navigate the system’s GUI. When using other browsers some slight problems with displaying content may occur.


System as a guest in virtual environments

    Hyper-V:
    System doesn't work correctly as a Hyper-V virtual machine (guest). There are issues with hv_netvsc network driver.
 
    VMware ESXi:
    In case of installing the system as a VMware ESXi guest please use the following settings:
       - Guest OS: Other 2.6.x Linux ( 64bit )
       - Number of Cores: 4
       - Memory: Minimum 8GB
       - Network Adapter: VMXNET 3
       - SCSI Controller Type: Paravirtual or LSI Logic SAS
       - Boot Disk : 20GB Thick Provision
       - Add at least 6 virtual disk
       - Edit Settings->Options->Advanced-General->Configuration-> Add row: disk.EnableUUID : TRUE


Reclaim deleted blocks on thin-provisioned LUNs in various systems

    In case of deleting large amounts of data, reclaimed deleted blocks on thin-provisioned LUNs in Windows 2012 can significantly slow down system performance. If you predict frequent deletions of large amounts of data, we recommend turning off the automatic reclaim function in Windows 2012. This can be done by disabling the "file-delete notification" feature in the system registry. To do so, follow the steps below:
       - start Registry Editor.
       - locate the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem       
       - double-click DisableDeleteNotification.
       - in the Value data box, enter a value of 1, and then click OK.
 
    In order to reclaim the free space in Windows 2012 please change the    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\DisableDeleteNotification key value back to 0 and use "Optimize" tool located in Disc Management->[disk]->Properties->Tools. As the operation can generate a very high load in the system, it is recommended to perform it after-hours.  
In case of VMware ESXi, the automatic reclaim feature is disabled by default. To reclaim the space of deleted blocks on thin-provisioned LUNs, please use vmkfstools. For details, please refer to the VMware Knowledge Base : http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014849
 
    In case of using Windows 2008 or Citrix Server there is no possibility to reclaim the space released by deleted data of thin-provisioned LUNs.


Deduplication issues and recommendations

    Please be aware that deleting the zvol with deduplication enabled can generate a very high load in the system and lead to unstable behavior. It is strongly recommended to perform such operation only after-hours. To avoid this issue, please use (if possible) single zvol on zpools dedicated for deduplication and delete the zpool which includes the single zvol.
   
    To determine the amount of System RAM required for deduplication, use this formula:
 
                                                                                                                    (Size of Zvol / Volume block size) * 320B / 0.5 / 0.25
 
Where:
320B - is the size of entry in DDT table
0.5 - Percentage of RAM reservation for ARC (50%)
0.25 - Percentage of DDT reservation in ARC (25%)
 
     Example for 1TB data and 64KB Volume block size:
 
(1099511627776B / 65536B) * 320B / 0.5 / 0.25 = 42949672960B
42949672960B / 1024 / 1024 / 1024 = 40GB
 
so for every extra 1TB of storage, system needs extra 40GB RAM.

     Example for 1TB data and 128KB Volume block size:
 
(1099511627776B / 131072B) * 320B / 0.5 / 0.25 = 21474836480B
21474836480B / 1024 / 1024 / 1024 = 20GB
 
so for every extra 1TB of storage, system needs extra 20GB RAM.

Zvols configuration issues and recommendations

     It is strongly recommended to set the client file system block size same as the zvol volume block size. For example, when using 64k zvol volume block size, the Windows Allocation unit size of NTFS should be set to 64k.


Target number limit

    More than 20 targets in the system can cause the Web Browser to demand termination of JavaScript. Please answer "wait".
    In case of more than 60 targets, GUI will not be displayed correctly. This issue will be fixed in the next releases.

Targets with the same name are not assigned correctly

    Having two or more targets with the same name but belonging to various Zpools, will cause that all targets with the same name will be assigned to one Zpool during the import process.


Installation on disks containing LVM metadata

     There is no possibility to install the system on disks containing LVM metadata. You will need to clear those disks before installation. To do so, use the “Remove ZFS data structures and disks partitions” function located in the Extended tools. To access this function, boot the system from a temporary media like a USB drive or DVD.

Import Zpool with broken write log

     There is no option to import Zpool with a broken write log disk using the system’s functions. This is why it is STRONGLY recommended to use mirrored disks for write logs. In case it is necessary to import Zpool with a broken write log, please contact technical support.


Replacing disks in data groups for larger ones can cause your storage license capacity to be exceeded

     In case of replacing damaged disks for larger ones, the size of the entire Zpool will increased. Make sure that the new size will not exceed your purchased storage license.

Periodically after some operations, the GUI needs to be manually refreshed

     After performing some operations, e.g. resilvering, the GUI will show outdated information. In this case refresh the web page manually by pressing F5 on your keyboard. This issue will be fixed in next releases.


Replacing disks in data groups for smaller ones can cause an error and make the disk disappear from the list of available disks

     Operation of replacing a disk in a data group for a smaller one will cause an error "zpool unknown error, exit code 255", and the disk will become unavailable. In order to reuse this disk, please use function "Remove ZFS data structures and disks partitions" located in the Extended tools on the Console screen.


     Smaller than 64KB block sizes used with deduplication or read cache will cause very high memory consumption.



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