Mohammad Banikazemi

Meridian: an SDN platform for cloud network services

As the number and variety of applications and workloads moving to the cloud grows, networking capabilities have become increasingly important. Over a brief period, networking support offered by both cloud service providers and cloud controller platforms has developed rapidly. In most of these cloud networking service models, however, users must configure a variety of network-layer constructs such as switches, subnets, and ACLs, which can then be used by their cloud applications. In this article, we argue for a service-level network model that provides higher- level connectivity and policy abstractions that are integral parts of cloud applications. Moreover, the emergence of the software-defined networking (SDN) paradigm provides a new opportunity to closely integrate application provisioning in the cloud with the network through programmable interfaces and automation. We describe the architecture and implementation of Meridian, an SDN controller platform that supports a service-level model for application networking in clouds. We discuss some of the key challenges in the design and implementation, including how to efficiently handle dynamic updates to virtual networks, orchestration of network tasks on a large set of devices, and how Meridian can be integrated with multiple cloud controllers.

PAM: a novel performance/power aware meta-scheduler for multi-core systems

Sharing resources such as caches and main memory bandwidth in multi-core systems requires a more sophisticated scheduling scheme. PAM is a low-overhead, user-level meta-scheduler which does not require any hardware or software changes. In particular, it operates by detecting resource congestions and providing guidelines to the standard system scheduler by limiting the assignment of processes to subsets of available cores. PAM contains a cache model that it uses to predict the impact of new schedules. PAM can be used to improve the system along three dimensions: performance, power, and energy consumption (and any combination of these three). On our prototype, we show individual benchmarks can improve by up to 33% and the overall system performance can be improved by as much as 14%.

Storage-based intrusion detection for storage area networks (SANs)

Storage systems are the next frontier for providing protection against intrusion. Since storage systems see changes to persistent data, several types of intrusions can be detected by storage systems. Intrusion detection (ID) techniques can be deployed in various storage systems. In this paper, we study how intrusions can be detected at the block storage level and in SAN environments. We propose novel approaches for storage-based intrusion detection and discuss how features of state-of-the-art block storage systems can be used for intrusion detection and recovery of compromised data. In particular we present two prototype systems. First we present a real time intrusion detection system (IDS), which has been integrated within a storage management and virtualization system. In this system incoming requests for storage blocks are examined for signs of intrusions in real time. We then discuss how intrusion detection schemes can be deployed as an appliance loosely coupled with a SAN storage system. The major advantage of this approach is that it does not require any modification and enhancement to the storage system software. In this approach, we use the space and time efficient point-in-time copy operation provided by SAN storage devices. We also present performance results showing that the impact of ID on the overall storage system performance is negligible. Recovering data in compromised systems is also discussed.

Software defined networking to support the software defined environment

Software defined networking (SDN) represents a new approach in which the decision-making process of the network is moved from distributed network devices to a logically centralized controller, implemented as software running on commodity servers. This enables more automation and optimization of the network and, when combined with software defined compute and software defined storage, forms one of the three pillars of IBMs software defined environment (SDE). This paper provides an overview of SDN, focusing on several technologies gaining attention and the benefits they provide for cloud-computing providers and end-users. These technologies include (i) logically centralized SDN controllers to manage virtual and physical networks, (ii) new abstractions for virtual networks and network virtualization, and (iii) new routing algorithms that eliminate limitations of traditional Ethernet routing and allow newer network topologies. Additionally, we present IBMs vision for SDN, describing how these technologies work together to virtualize the underlying physical network infrastructure and automate resource provisioning. The vision includes automated provisioning of multi-tier applications, application performance monitoring, and the enabling of dynamic adaptation of network resources to application workloads. Finally, we explore the implications of SDN on network topologies, quality of service, and middleboxes (e.g., network appliances).

Enhancing recovery using an SSD buffer pool extension

Recent advances in solid state technology have led to the introduction of solid state drives (SSDs). Todays SSDs store data persistently using NAND flash memory and support good random IO performance. Current work in exploiting flash in database systems has primarily focused on using its random IO capability for second level bufferpools below main memory. There has not been much emphasis on exploiting its persistence.n In this paper, we describe a mechanism extending our previous work on a SSD Bufferpool on a DB2 LUW prototype, to exploit the SSD persistence for recovery and normal restart. We demonstrate significantly shorter recovery times, and improved performance immediately after recovery completes. We quantify the overhead of supporting recovery and show that the overhead is minimal.

Storage-based file system integrity checker

In this paper we present a storage based intrusion detection system (IDS) which uses time and space efficient point-in-time copy and performs file system integrity checks to detect intrusions. The storage system software is enhanced to keep track of modified blocks such that the file system scan can be performed more efficiently. Furthermore, when an intrusion occurs a recent undamaged copy of the storage is used to recover the compromised data.

LZB: Data Compression with Bounded References

In this paper, we propose a new compression/decompression algorithm called LZB which belongs to a class of algorithms related to Lempel-Ziv (LZ). The distinguishing characteristic of LZB is that it allows decompression from arbitrary points of compressed data. This is accomplished by setting a limit on how far back a reference in compressed data can directly or indirectly point to. We enforce this limit by using a sliding gate. During the compression, we keep track of the origin of each input symbol.xa0xa0The origin of a symbol is the earliest symbol in the input data that the symbol (directly or indirectly) refers to. By using this information we avoid using any reference which go beyond the gate boundary.xa0xa0We modified the gzip implementation of LZ77 to implement LZB. We then compared LZB with the alternative method in which data is segmented into smaller pieces and each piece is compressed separately by using the standard gzip. The results show that LZB improves the compression ratio by 10 to 50 percent for 1024 to 128 byte segment sizes.

MetaData persistence using storage class memory: experiences with flash-backed DRAM

Storage Class Memory (SCM) blends the best properties of main memory and hard disk drives. It offers non-volatility and byte addressability, and promises short access times with low cost per bit. Earlier research in this field explored designs exploiting SCM features and used either simulations or theoretical models for evaluations. In this work, we explore the design challenges for achieving non-volatility using real SCM hardware that is available now: Flash-Backed DRAM. We present performance analysis of flash-backed DRAM and describe the system issues involved in achieving true non-volatility using the system memory hierarchy which was designed assuming that data is volatile. We present software abstractions which allow applications to be redesigned easily using SCM features, without having to worry about system issues. Furthermore, we present case studies using two applications with different characteristics: an SSD-based caching layer used in enterprise storage (Flash Cache) and an in-memory database (SolidDB), and redesign them using software abstractions. Our performance evaluations reveal that SCM aware Flash Cache design could enable persistence with less than 2% degradation in performance. Similarly, redesigning SolidDB persistence layer using SCM improved the performance by a factor of two. To the best of our knowledge, this is the first work that evaluates SCM performance and demonstrates application redesign using real SCM hardware.

Scalable data center provisioning and control

The problem of provisioning servers in a data center environment includes coordinating access to and sharing of physical resources, loading servers with the appropriate software images, supporting storage access to users and applications, and providing basic monitoring and control services for those servers. We have developed and adapted systems--Hop-scotch, Sysman, and the InfiniBande-attached IBM Storage Area Network (SAN) Volume Controller (SVC)--that automate the provisioning and monitoring processes for large collections of servers. Our solution relies on directory services to implement access control. It uses network boot disks and managed root disks to control the image of each server. We leverage the IBM Global Storage Architecture and SVC to provide storage to users and applications. Finally, interfaces are provided to access the services both programmatically and interactively.

Flipstone: managing storage with fail-in-place and deferred maintenance service models

The cost of managing storage systems has become one of the significant expense items in data centers. In this paper, we discuss the design and implementation of Flipstone, a new storage system with reduced storage management cost. Flipstone provides fail-in-place and deferred maintenance by aggregating large number of off-the-shelf, inexpensive storage systems. We show a significant improvement in total cost of ownership of storage systems by reducing the number of service calls when Flipstone is used.